Cheap Material For Test Cuts? Foam?

Hello all,
I hoping somebody in the community can possibly point me in the right direction on this.

My CNCRP kit is almost fully functional. I've cut out the Mach 3 roadrunner file in some scrap wood and such.

However, I'm hoping to be cutting electric guitar parts soon, but the wood used on these can be quite expensive to ruin while I'm still getting the hang of things.

Does anybody know of any cheap material that can be used for test cuts? Foam possibly? The problem is finding something with dimensions close to a guitar body blank. Typically I'd be using 1.75 in x 13 in x 20 in for a body blank.

I've already considered buying cheap lumber from home depot or lowes, BUT my problem with that is how time consuming it is to plane and glue up a body blank from the sizes of lumber available.

I've seen some listings for bulk foam, they either seem to be crazy expensive (like $30+ for something less than a body blank in size.....which I could just buy hardwood for that price) or exponentially cheaper bulk orders that require you buy 300 square meters or more.

Any advice?

I cut quite a few guitar parts, and use pink insulation foam for proofing. Home Depot sells 2" thickness, but you can machine it down to 1-3/4" just fine...

Awesome! Thanks so much for the advice louieatienza! I knew there had to be a more simple solution than what I was finding. I assume you surface down to 1.75 with a surfacing bit?

I imagine I could probably cut just under a quarter inch off with my bandsaw and then use a bit to make it flat again. I guess what I'm getting at is that this isn't the type of material you'd send through a planer right?

Why bother thinning it down? Reference everything from the top surface...it's not like you need to cut all the way through.

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Originally Posted by Lee DeRaud

Why bother thinning it down? Reference everything from the top surface...it's not like you need to cut all the way through.

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That's true if you don't have to actually mock up and hold the finished part; but in the guitar world feel is everything and people are finicky.

But NO, do NOT feed it through a planer! And be careful cutting it on whatever saw, because the heat can bind the board up and cause it to kick back. I use a jigsaw with a coarse blade to cut the board to rough size, or even a knife and straightedge, it will snap off easily. I have a 1-1/4" mortising it that I use to surface stuff including foam. I guess a bandsaw would be fine, as long as you're using a coarse blade. I would put shims to keep the kerf open...

Quote:

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Originally Posted by louieatienza

That's true if you don't have to actually mock up and hold the finished part; but in the guitar world feel is everything and people are finicky.

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I know what you mean, but if realistic feel is the goal, maybe foam isn't the right answer. I took the question to apply more to checking the critical dimensional relationships: neck pocket shape, bridge/pickup placement, etc.

Would MDF work for you, then again it isn't cheap but you could get a few bodies out of a single sheet. You could also look at stair treads maybe you could find some that will work (I think the normal thickness is around 5/4)

Ultimately I'd like to be able to mock up the finished product. Lee is correct for just testing out pockets and such, but I'd really like to test everything to a decent degree. I could see it also being useful for testing if the electronics cavity is routed deep enough, whether a particular neck carve feels good or needs some tweaking, how the body feels against your gut, how the body feels while sitting on your leg, etc.

For that matter it would be useful for me to make sure I've actually got a good zeroing system in place for when I flip the body and machine the back. I'm still pretty worried about that...

As for the mdf, I've considered it...but I think it'd be a nightmare. The dust that stuff generates when cut is brutal and gets everywhere. Couple that with still needing to glue pieces to make body blanks (assuming it glues well) and it just doesn't sound fun. All the mdf I see around here is 3/4. I appreciate the suggestion though.

You could easily get 8/4 poplar or basswood; cuts easily enough, and you can get them in wide widths, and at about $3/bdft if you go to a lumberyard. You don't have to breathe in formaldehyde like you would with MDF or God knows what with foam. D2S yields around 1-13/16" thickness which is perfect for most solidbody guitars. Usually a lumberyard could cut an end off for you as long as it leaves a 6' board.

If you have a dust collector mdf is a non issue. Infact if you don't have a dust collector your really going to want one!

I usually prototype in poplar 1c grade, it's available here for $1.39 a board foot. 9 times out of 10, I end up selling the prototype as a paint grade body.

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All pretty good advice. I'm in the process of putting together dust collection now...and I haven't gotten to see how good it will be, but I just have trouble thinking that it will get 100% of mdf debris even if it's excellent.

I actually bought a load of poplar not long ago for this explicit purpose. I can get some for about 80 cents per bd foot here. The problem is that it's only 4/4 and typically wet and thus needs drying time. It's also a 45 min drive each way to get it. Were I to go to a legit lumber mill, it would be 2 hours each way from where I live and significantly more expensive. So while I'll most likely be using poplar on the true prototypes, it sounds like the foam will be great for practice cuts or just experimenting with neck shapes, etc. Thanks for all of the advice everyone!