Author Topic: Building first Bingham Take Down Recurve bow - few questions for you guys (Read 2228 times)

kenboonejr · « **on:** July 03, 2021, 08:56:05 PM »

So I bought my take down recurve bow kit like 4 years ago, right after I made a red oak board bow thanks in part to this site and started a few other board bows. Then I hurt my left shoulder and had to have surgery. I recovered from that then got a SLAP tear on my left shoulder and had to recover from that. Once that got back to normal my right shoulder went bad and had to have surgery on that. So now I am back to 90% and decided it was time to make this take down recurve. The kit has been stored in the box it came in 4 years ago in my office so it has been in a temperature controlled environment. I finally opened up the kit this weekend. So here are my questions?

The kit came with Smooth On part A and part B. Do you think this is still good after sitting on the shelf if you will for 4 years?

The metal strip that will be used in the form when glueing the laminations together has somewhat of a sharp bent/dent in it about 1/3 of the way down it. Will that flatten out and be ok once pressure is applied in the form or should I get another one?

Last question. I know lumber has gone up, but I myself have not been out to purchase lumber. The heat box plans call for two 4x8 sheets of exterior plywood 1/2" thick. I went to the store today and they were $71/sheet. I knew prices went up but I didn't realize how high. Just wondering at those prices can I step down to OSB? or something different even? Just wondering on what your thoughts are on that. I would assume OSB could hanldle the heat that will be put in it. At least that is my assumption. Although the OSB is only slightly cheaper than the plywood.

Thanks!

Mad Max · « **Reply #1 on:** July 03, 2021, 10:01:37 PM »

get some New smooth on, get the smallest one, you can hammer out the dents on the pressure strip and file and sand the sharp edges

Smooth-on will cure at room temp. 70* in 24 hours and that will be fine, if your truck is hot inside it you can put your form in there to cure, 140* ish maybe, according to where you live. don't forget to put down some cardboard or old blanket to protect your truck from the smooth on drippings. You can wait on making a hot box until later, some do not even use one.
Some use a electric blanket around the form and maybe more regular blankets over the top of that to hold in more heat. Poke a thermometer threw the electric blanket, even at 120* will work for 8 hours or so.

put 50psi. in your fire hose and stick each end in a bucket of water to check for leaks.

Last thing , Take your time

Longcruise · « **Reply #2 on:** July 03, 2021, 10:07:50 PM »

I would replace the Smooth On. It may be ok and then again maybe not!! Save it for repairs around the house 🏠.

The dent in the pressure strip is not a problem.

You don't need an oven at all. Smooth On will cure in 24 hours at 72 degrees. Options to speed it up; put it in a car in the hot sun; wrap black plastic around it and put it in the sun; throw an electric blanket over it. I've done all of those without problems.

Longcruise · « **Reply #3 on:** July 03, 2021, 10:09:36 PM »

Max, you type faster than me! 😀

Mad Max · « **Reply #4 on:** July 03, 2021, 10:37:59 PM »

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kenboonejr · « **Reply #5 on:** July 04, 2021, 09:17:50 AM »

@Mad Max @Longcruise
Guys,
Thanks for the great responses. I will take your recommendations and get some fresh smooth on! That's a relief that I don't need to build the hot box. I just couldn't believe those prices. Still need to go get some wood for the form though. Hope to get that today and get started on the form. So worst case scenario is it will cure in 24 hours where I am (SC) or I was thinking about the comments you guys made about my truck. I'm gonna throw a thermometer in the bed of my truck which is covered by a black aluminum bed cover and see how hot that gets. I guess that leads me to one additional question. Everything I have seen on heating these forms always shows the forms standing up. Once everything is locked down tight is it okay to put them on their side - like if I do put it in the bed of my truck?
Thanks again!

kennym · « **Reply #6 on:** July 04, 2021, 10:35:12 AM »

My 5 year old hunting bow was cured at 70* on the bench just to see, no probs with it yet but I don't expose it to a lot of heat. I had heard some bowyers weren't heating so I had to see. The thinking is if you heat the cure, the bow will stand more heat after without delamming.

That said, I cure them all after that. Overlays I never heat,and use the older glue on sometimes , they can be put back on unlike the limbs.

Smooth on has a 2 year shelf life now also.

Form on it's side is fine.

Good luck and have fun!!

Tim Finley · « **Reply #7 on:** July 04, 2021, 12:39:16 PM »

Kenny is right you need to heat to have heat resistance from hot cars deer blinds or just plain hot days at the range . Any epoxy you heat cure will be stronger . I reheat mine usually twice but with some bows and more overlays they may go back in 5 times although not as hot as the first cure .
I talked to the chemist from smooth on and he said you can reheat up to the original cure and and it goes back to the same strength after it cools.

kenboonejr · « **Reply #8 on:** July 04, 2021, 03:38:15 PM »

Guys,
I appreciate all the good info. I purchased the wood for the forms today and placed an order for some fresh Smooth On. Hoping to get the form built in the next few days and by the time that is ready hopefully the Smooth On will be here. I am going to temp check my truck bed and see how hot that gets and try to use that method I think. Thanks again I'm looking forward to getting this going.
Thank you!

kenboonejr · « **Reply #9 on:** July 04, 2021, 06:42:28 PM »

I'm sorry one more question..

So I know I can call Binghams and ask them this but I figure they are probably closed tomorrow and then I would have to wait until Tuesday evening to start. See where I am going? Anyway, my bow build is for a 1.75" bow, so the lams, pressure strip etc is 1.75" wide. The instructions only talk about building a 2" form. I know I have read stuff here where it seems like folks build the form to the exact size of the lams. So do I move forward with laminating plywood together to form a 2" form or do I need to make sure it is 1.75" I "think" I would need to do 1.75 but figured I would double check with you guys.
Thanks again!

Mad Max · « **Reply #10 on:** July 04, 2021, 08:12:17 PM »

1-3/4" is what you want

kenboonejr · « **Reply #11 on:** July 04, 2021, 09:44:55 PM »

Thanks Mad Max! Plan to get them glued up tomorrow!

Longcruise · « **Reply #12 on:** July 04, 2021, 10:38:39 PM »

Also, for each glue joint or sheet that you use to get to 1.75", you will lose 1/32". It's not much but depending on how many sheets you glue up it will add up.

kenboonejr · « **Reply #13 on:** July 04, 2021, 10:43:12 PM »

What do you recommend then as far as size of plywood sheets to glue together. It seems like my only option is to use one 3/4" and two 1/2". So I will be 3/32 short of the 1.75". How critical is that or is there a different way I should be doing this?
Thanks again!

jess stuart · « **Reply #14 on:** July 05, 2021, 12:22:43 AM »

Others will recommend against it but, I have had great success using MDF. You need to protect it from moisture I also skin it with thin plywood. The thickness it comes in are very close to the actual thickness unlike plywood. Another option is using LVL, I haven't personally used it but others have had great success with it. Good luck on your build.

Longcruise · « **Reply #15 on:** July 05, 2021, 01:45:05 AM »

I use roofing felt as a filler. That may not be ideal. There may be better ways of handling it. I do it that way because I have it on hand.

kenboonejr · « **Reply #16 on:** July 05, 2021, 09:01:39 AM »

Yea I figured if I oversized it and then tried to plane down the plywood that that would not go well. I'm gonna look around in my barn and see what I can use for filler.

Jeff Freeman · « **Reply #17 on:** July 05, 2021, 11:18:15 AM »

All plywood does not actually measure what it says take your calipers to the lumber yard with you see what you can find Don't forget about 1/8 inch hard board as a spacer. Or the thinner plywoods but take your tape measure and calipers and measure up see what you can come up with. JF

Shredd · « **Reply #18 on:** July 05, 2021, 01:08:53 PM »

This is what I use for a filler...

https://www.homedepot.com/p/Ram-Board-042-in-x-38-in-x-50-ft-Temporary-Floor-Protection-Board-5008195/202829135

Mad Max · « **Reply #19 on:** July 05, 2021, 02:58:42 PM »

Quote from: Shredd on July 05, 2021, 01:08:53 PM

This is what I use for a filler...

https://www.homedepot.com/p/Ram-Board-042-in-x-38-in-x-50-ft-Temporary-Floor-Protection-Board-5008195/202829135

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Author Topic: Building first Bingham Take Down Recurve bow - few questions for you guys (Read 2228 times)

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