Pay N Pak

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Are you scratch building it, or is it a Dumas kit? What size engine is it for? Ive built a 20 and a 40 size Pak from Dumas kits and am building 60 size Pak also from a Dumas kit....There is also a gentleman that goes by Hydro Junkie that has a bunch of experience with that type of boat that will chime in, im sure....are you going to build the '73,74,75 piston engine version? Thats what im building or TRYING to build.....

Hi guys,

If its the Dumas kits, then its a simple board. On the sport 20 Pak Its a 1 X 7-5/8 X 30". On the sport 40 size i used a 1 X 9 X 32". If its the 8th scale I would reconmend same thing, just measure the tunnel width X hull length. your gonna have to shim the building board about an inch or so, to allow for the sponson bottoms.

I assembled the sponson stringers and cockpit insides and frames 1-9 loosely on the jig. Then using a square edge or triangle, I made sure that the sponson stringers were flat against the board and that all frames were squared up even...i then used thumb tacks and tacked down the sponson stringers to the building board. using a machinist ruler I checked my height on both stringers to make sure all was in alignment. I then proceeded to epoxy the frames and cockpit sides in place....making sure that they laid flat against the building board evenly.

Dont forget to use wax paper or similar or you may end up glueing your board to your boat....

as far as tips and pointers, it may depend on what your intentions are. Do you want a fun boat, or would you want to race it?

Hydro Junkie offers some building suggestions that are sound, however require's a total rebuild of the basic hull design, depends if you want to keep the Dumas flavor (if thats what you have)then build it according to the instructions. If you want a little bit more from it, then I say follow his advice.

I would simply suggest using a dremel router and make some lightening holes in most of the frames and stringers in an attempt to lose some weight. Move the radio box as far forward as possible and use known quaility running hardware.....

Enjoy!

Ron

Bill Gibson said:

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Are you scratch building it, or is it a Dumas kit? What size engine is it for? Ive built a 20 and a 40 size Pak from Dumas kits and am building 60 size Pak also from a Dumas kit....There is also a gentleman that goes by Hydro Junkie that has a bunch of experience with that type of boat that will chime in, im sure....are you going to build the '73,74,75 piston engine version? Thats what im building or TRYING to build.....

Click to expand...

Okay Bill, my ears started ringing. I have to ask the same thing, are you building from plans and if so, from who, or a kit? There is a considerable amount of difference between the various plan sets and the Dumas kit, so knowing which boat and size you are building will make answering your question much easier

Bill, since when am I called a gentleman? I thought I was a royal rat

Hydro Junkie said:

Bill Gibson said:

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Are you scratch building it, or is it a Dumas kit? What size engine is it for? Ive built a 20 and a 40 size Pak from Dumas kits and am building 60 size Pak also from a Dumas kit....There is also a gentleman that goes by Hydro Junkie that has a bunch of experience with that type of boat that will chime in, im sure....are you going to build the '73,74,75 piston engine version? Thats what im building or TRYING to build.....

Click to expand...

Okay Bill, my ears started ringing. I have to ask the same thing, are you building from plans and if so, from who, or a kit? There is a considerable amount of difference between the various plan sets and the Dumas kit, so knowing which boat and size you are building will make answering your question much easier

Bill, since when am I called a gentleman? I thought I was a royal rat

Click to expand...

I built a 60 size a couple years ago and followed the Dumas instructions for building the jig-it was so bad I gave it to my neighbor for kindeling in her fireplace. Ended up using the building jig/boat stand I made for the Dumas AVL boat I built almost 30 years ago.

Glenn

glenng said:

Hydro Junkie said:

Bill Gibson said:

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Are you scratch building it, or is it a Dumas kit? What size engine is it for? Ive built a 20 and a 40 size Pak from Dumas kits and am building 60 size Pak also from a Dumas kit....There is also a gentleman that goes by Hydro Junkie that has a bunch of experience with that type of boat that will chime in, im sure....are you going to build the '73,74,75 piston engine version? Thats what im building or TRYING to build.....

Click to expand...

Okay Bill, my ears started ringing. I have to ask the same thing, are you building from plans and if so, from who, or a kit? There is a considerable amount of difference between the various plan sets and the Dumas kit, so knowing which boat and size you are building will make answering your question much easier

Bill, since when am I called a gentleman? I thought I was a royal rat

Click to expand...

I built a 60 size a couple years ago and followed the Dumas instructions for building the jig-it was so bad I gave it to my neighbor for kindeling in her fireplace. Ended up using the building jig/boat stand I made for the Dumas AVL boat I built almost 30 years ago.

Glenn

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I am building a 20 size kit from dumas. This is my first time building so I think it is going to be a challange but fun.

Oaky Griz..as RJ did, i built my 20 Pak using nothing more than a flat board at those dimensions...but since its your first build lets throw a coupla more bits of info out there for you...there are a couple of approaches to building that boat....i built mine using the stock materials that came with the kit, and it worked fine..i had a great time building and running that little boat in its stock form...HOWEVER,and i hope that this where HJ will jump in, there are better materials and changes that you can make to that boat to make it run much better than stock...if you want to build it and just play with it the way it is that is perfectly fine, like i said, i had a great time with mine in its stock form...if you would like to make it better than stock, it can be done....Calling HYDRO JUNKIE....he can help greatly with option #2! Not tryin to confuse you Griz, just want to give you some things to consider BEFORE you start the build...you know.. before the glue has already dried! And you WILL have fun building it either way!

Okay Bill, my ears were ringing again. I'm not going to give you one option, I'm going to give you options 2 AND 3

Option 2 is a partial replacement of the framing. Nothing real drastic, just some improvements in hull strength and ease of finishing.

Step 1 is to take the sponson insides and use them as a pattern to trace around on some 1/8th aircraft plywood. The only changes we're going to make is to add to the tab at the back so that it's 3/16 to 1/4" long and after the framwork is assembled, cut some lightening holes out of them

Step 2 is to do the same as step 1 using the engine bay walls, again lengthening the tab at the back, but this time, use 1/16th aircraft plywood and don't cut lightening holes.

Step 3 is to use the inside part of the transom and trace around it on either 3/16 or 1/4 aircraft plywood. Cut the slots all the way through and be sure to cut the engine bay wall slots 1/16 thick to either the inside or outside of the slot in the supplied part so you don't have to fill any gaps in the transom

Step 4 is to replace the sponson transom in the same way as the lengthwise frames using 1/8th aircraft plywood

Step 5 is to assemble as directed but with 3 changes:

1) install 1/8" square glue blocks along the bottom of the boat where the bottom is glued on to the sponson insides, top and bottom edges of the engine bay walls and along the top of the nontrips where the deck is attached

2) laminate a doubler inside the right sponson transom covering the entire inside and be sure it's glued to the sponson inside as well. This needs to be 1/8th or 3/16ths thick aircraft ply

3) forget about using Dumas hardware, I'd recommend Speedmaster, Octura or other comparable brands. Also, don't install the engine blocks as directed, there are much better ways of installing an engine. Have all the hardware mounted before installing the deck. Anyplace the directions say to use wood screws, use blind nuts instead. Be sure they are installed with epoxy as well

Rather than make my last post massive, I decided to make option 3 as it's own post. This one is a partial redesign as well, so it will take some work. If this seems like too much to handle, don't attempt it. With that being said, here we go.

Step 1. Trace around ALL the framing parts using 1/16th ply instead of 1/8 except the sponson sheers, they need to be 1/8. Be sure to lengthen the tabs like in option 2. One change you can make is to widen the engine bay to 4" if it's not that wide from the factory. I can explain that proceedure if needed later. Mark but do not cut any of the interlocking slots on any parts for now. Cut out all the parts and set asside all but the furthest forward frame, radio box front, transom and one sponson inside

Step 2. Cut the slots for the furthest forward frame and the front of the radio box in the sponson inside and the interlocking slot in this part of the frame only. Be sure the slots are big enough for the frames to fit without being tight. Excess space isn't good.

Step 3. Slip the two frames and transom into the slots cut in the sponson inside and, using a straigh edge, draw a line from the bottom of the transom to the radio box front and then to the front frame. This gives you the modified bottom profile. Glue a 1/8" piece of square spruce along the top of this line. Now repeat the process on the other sponson inside, making sure there is a left and a right

Step 4. Cut out the remaining slots, again making sure they are not sloppy or tight in fit. You will need to modify the frame between the front frame and radio box front as the bottom will be higher in this area than in the stock kit. You will also need to notch the frames to clear the previously installed glue blocks. Dry assemble the framework and mark the engine bay walls so they match the new bottom profile, remove the excess and install glue blocks along the bottom edge again making sure there is a left and a right. Reinstall the engine bay walls with the glue blocks facing the sponson insides

Step 5. Install the bottom as described in the kit instructions. You may need to use new material if the boat was widened or the supplied parts no longer will work.

Step 6. Cut lightening holes out of all the underdeck framing. This will lighten up the hull and make draining any water that may get in possible. When you're finished, the boat will look like this, except without the sides and sponsons skinned. In the case of my boat, I made several changes, such as moving the fuel tank under the deck with a bottom access hatch and running the cooling lines under the deck, but all that will come later. If this looks like something you want to try I can go further later

Awesome info. I will be racing it so I will go with the info from you guys. Thanks alot. Now if I wanted to build a 40 and 60 size how do I go about that? Do I do bigger scale or is it easier to get the plans from newton? (it will be when I'm done with this project)

griz2575 said:

Awesome info. I will be racing it so I will go with the info from you guys. Thanks alot. Now if I wanted to build a 40 and 60 size how do I go about that? Do I do bigger scale or is it easier to get the plans from newton? (it will be when I'm done with this project)

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The boat I showed you is a scaled down Newton and is the way I would go. I made a few slight mods to the plans, not much though. If you want to build from plans, you might want to go with option 3 as it's based on a plans build. I only made one real change in the design, that being the bottom profile, but if I were building the boat, I would have made more, but that's me

Hydro Junkie said:

griz2575 said:

Awesome info. I will be racing it so I will go with the info from you guys. Thanks alot. Now if I wanted to build a 40 and 60 size how do I go about that? Do I do bigger scale or is it easier to get the plans from newton? (it will be when I'm done with this project)

Click to expand...

The boat I showed you is a scaled down Newton and is the way I would go. I made a few slight mods to the plans, not much though. If you want to build from plans, you might want to go with option 3 as it's based on a plans build. I only made one real change in the design, that being the bottom profile, but if I were building the boat, I would have made more, but that's me

Click to expand...

And that my friend is why id hoped youd get in on this one.....A first time builder just got alot of GOOD information!

So I take that as Bill's vote of approval. Guess I said something right :lol:

Heres a pic of my Dumas Pay N pak 20.

First, I cant beleive that they actually mention using wood screws for the turn fin & rudder...I'm using Speedmasters .21/40 rudder and square bottom strut. The turnfin I picked up from a hong kong seller on ebay. I used 6-32 T-nuts for my turnfin mount (1/8 ply doubler on inside)

I was going to go ahead and use this engine mount, instead of the dumas one...

I wanted to keep the Dumas flavor and built it according to the plans more or less. What I've done was to make cutouts in all the frames & bulkheads in an attempt to keep the weight down. I did add 1/8 square stock along the bottom like HJ says as well as the top deck, especially along the non trip chines.

My next step was to remove the bulkhead 7, and just make bulkheads 5 & 6 my radio box.

The hull feels really light as of now. However I took a bottle of drinking water, which weighs .09 ounces (.5liter) and its definately heavier than the hull....

I remember that the cowl took almost as long to build as the hull on my 40 size U-76, I'm pretty much expecting the same here......

Cool trick that I'l share, I used my wifes iron and by holding and bending the sponsons sides and decks, I was able to get a nice bend in them so that they may fit over curves better. Just sprinkle a little bit of water over the area you want to bend and put the iron over your 1/16 ply skin and gently pull up and pressing down on the iron you'l get a nice bend....

When I epoxied the decks on, I placed the hull upside down so that the epoxy would flow onto the underside of the deck, instead of flowing down over the frames....

R.J.West said:

Heres a pic of my Dumas Pay N pak 20.

First, I cant beleive that they actually mention using wood screws for the turn fin & rudder...I'm using Speedmasters .21/40 rudder and square bottom strut. The turnfin I picked up from a hong kong seller on ebay. I used 6-32 T-nuts for my turnfin mount (1/8 ply doubler on inside)

I was going to go ahead and use this engine mount, instead of the dumas one...

I wanted to keep the Dumas flavor and built it according to the plans more or less. What I've done was to make cutouts in all the frames & bulkheads in an attempt to keep the weight down. I did add 1/8 square stock along the bottom like HJ says as well as the top deck, especially along the non trip chines.

My next step was to remove the bulkhead 7, and just make bulkheads 5 & 6 my radio box.

The hull feels really light as of now. However I took a bottle of drinking water, which weighs .09 ounces (.5liter) and its definately heavier than the hull....

I remember that the cowl took almost as long to build as the hull on my 40 size U-76, I'm pretty much expecting the same here......

Cool trick that I'l share, I used my wifes iron and by holding and bending the sponsons sides and decks, I was able to get a nice bend in them so that they may fit over curves better. Just sprinkle a little bit of water over the area you want to bend and put the iron over your 1/16 ply skin and gently pull up and pressing down on the iron you'l get a nice bend....

When I epoxied the decks on, I placed the hull upside down so that the epoxy would flow onto the underside of the deck, instead of flowing down over the frames....

Click to expand...

RJ...Ditto on the wood cowls...it does seem to take as long to build as the hull itself! Sounds like your doing everything right...thats a GREAT little motor...ive got one in a 20 rigger and its been one of the most dependable and easy to needle motors ive ever owned..im using a set of those Solinger mounts in a Sport 20 hydro that im building....too easy! I LIKE EM! Keep us posted on your progress..cant wait to see a pic of it all finished and skimmin across the pond! Wood Boats rule!

RJ, is that the Pak or the Atlas you pictured? if it's the Pak, it's been too long since I've seen one unfinished since I forgot about two of the frames up forward. My suggestion of moving the break in the bottom aft one frame still applies, just means altering three frames instead of one. I'm still at a loss on why Dumas would give the boat an almost barge-like front in the tunnel and recommend wood screws. I guess someone wasn't thinking clearly or something :huh:

One thing I would have done different, RJ, is I would have moved the skid fin further out toward the sponson outside instead of putting it dead center. Personal preference in this case

R.J.West said:

Heres a pic of my Dumas Pay N pak 20.

First, I cant beleive that they actually mention using wood screws for the turn fin & rudder...I'm using Speedmasters .21/40 rudder and square bottom strut. The turnfin I picked up from a hong kong seller on ebay. I used 6-32 T-nuts for my turnfin mount (1/8 ply doubler on inside)

I was going to go ahead and use this engine mount, instead of the dumas one...

I wanted to keep the Dumas flavor and built it according to the plans more or less. What I've done was to make cutouts in all the frames & bulkheads in an attempt to keep the weight down. I did add 1/8 square stock along the bottom like HJ says as well as the top deck, especially along the non trip chines.

My next step was to remove the bulkhead 7, and just make bulkheads 5 & 6 my radio box.

The hull feels really light as of now. However I took a bottle of drinking water, which weighs .09 ounces (.5liter) and its definately heavier than the hull....

I remember that the cowl took almost as long to build as the hull on my 40 size U-76, I'm pretty much expecting the same here......

Cool trick that I'l share, I used my wifes iron and by holding and bending the sponsons sides and decks, I was able to get a nice bend in them so that they may fit over curves better. Just sprinkle a little bit of water over the area you want to bend and put the iron over your 1/16 ply skin and gently pull up and pressing down on the iron you'l get a nice bend....

When I epoxied the decks on, I placed the hull upside down so that the epoxy would flow onto the underside of the deck, instead of flowing down over the frames....

Click to expand...

Decking, sponson sides and bottoms can also be bent to fit just using hot water and taping the heck out of em(on the hull) and just walk away for a couple days. Room temp.-not some cold garage. Don't bother sanding the skins before you do this as it will raise the grain a little.

Glenn

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Whatever jig you use I recommend you make it out of heavy duty water resistent particle board. That stuff is really dead and plywood tends to warp. I have always used Liquid Nails and clamps. I always get a smaller pice of particle board, cover it with wax paper and build the sponsons on that. Then I push pin the sponsons on to the main jig that you already the bottom and transom on. That way you can really do a good job of measuring to make sure you get a straight boat.

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Mike Cathey said:

griz2575 said:

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Click to expand...

Whatever jig you use I recommend you make it out of heavy duty water resistent particle board. That stuff is really dead and plywood tends to warp. I have always used Liquid Nails and clamps. I always get a smaller pice of particle board, cover it with wax paper and build the sponsons on that. Then I push pin the sponsons on to the main jig that you already the bottom and transom on. That way you can really do a good job of measuring to make sure you get a straight boat.

Click to expand...

I think the particle board you're talking about is called MDF(no I don't know what it stands for). Lowes or home depot shelving dept. 1" thick cut to width on a table saw. And use the wax paper so you don't glue the boat to the jig.

Glenn