Tips for making curved part on gunbox with basswood

Equipment Proton Packs
1

When I first started building my pack out of basswood and mdf, the first part I tried to tackle was my gunbox.

Of course, being my first attempt at building any part of the pack, or anything out of basswood for that matter, of course I screwed it up, and made the front of the box at the wrong angle, and made it much thicker than it needed to be by using 3/16" basswood.

So, now that I’ve built most of the rest of the pack, I decided to revisit the gun box. Tossing out the old work, I started from scratch using 1/8" basswood like on the rest of my pack. Not only will this result in a lighter gun box, but it will look better in the grill in the top of the box to have thinner wood there.

The tip I wanted to post about though is not about the thickness of the wood, but what I did last night, which was make the curved part on the gunbox.

Originally when I built the gunbox, I thought the best way to make that part would be to simply round the box over there by sanding. But since the radius of the bend is so large, to ensure enough material would be there, I either had to backfill with wood, or with wood filler. I chose the wood filler, like a dummy. I also used wood filler in all the corners of the box to reinforce it, which was also unneccessary, and looks messy.

Anyway, last night, a better method came to mind to make the curve. Since I’m working with wood, why not simply bend it?

I knew it was possible to do this, but on such a small piece of wood I thought there was no way I was going to be able to bend it to the right radius.

Then it occured to me that I’d been thinking about the problem from the point of view of bending the wood WITH the grain, and with a harder wood. What if I tried to bend it against it? And just how soft might basswood become if I soaked it anyway?

Having seen people bending wood on woodworking shows as a lad, I knew that the best way would probably be to steam the wood. On my first attempt I soaked the wood under the faucet for a few minutes and then wrapped it in wet paper towels and microwaved it for 30 seconds. When it came out, it was certainly pliable, but it remained so for only a very brief period, and as I tried to bend it around the circumference of my handles, it snapped in half, which was one of my concerns in regards to bending against the grain.

The next day I made a second attempt.

The previous day, having been an experiment, I didn’t bother to calculate exaclty how wide my piece of wood needed to be. I also had attemptded to bend the wood around PVC with a 1" OD. Yesterday however, after doing a bit of research, I decided to go with 1.25" OD PVC for my gun handles instead. Besides being more accurate, this had a secondary benefit. The larger diameter meant I didn’t have to bend the wood quite so much.

I also did a little calculation to figure out how wide a piece of wood I needed. Since I was starting with a handle 1.25" in diameter, and my wood was 1/8" or 0.125" thick, the outer diameter of my bend would be 1.375". Plugging that into the equation Circumference = Pi * Radius^2, and then dividing by 4 since I only needed one quarter of a circle, (90 degree bend) I determined that the wood would need to be exactly 1/2" wide, across the grain.

I didn’t figure the exact length, but using a bit of PVC as a guide, I figured 3" would be enough to ensure once I glued it in place I’d be able to saw it off at an angle to be flush with the front of the gun box at both the top and bottom.

Once I had this information, I cut the wood, soaked it under the tap for a minute, and placed it in a mug full of water, which I then microwaved for the standard length of time to heat a cup of coffee.

Taking the wood out of the mug while wearing a pair of rubber gloves so as not to burn myself, I then proceeded to burn myself as I bent the wood around my PVC handle. The wood quickly cooled, but not as quickly as before and not before I was able to bend it to fit the pipe, and get six rubber bands over it to hold it in place.

After doing this, I tried shocking it under cold water hoping that would be enough to make it retain its shape, as worked for my plastic tubing, but removing the rubber bands after, I found that was not the case, and put them back on and left it to dry overnight.

And in the morning, I found I had achieved success, and am now the proud owner of a piece of basswood that has a beautiful and permanent 90 degree curve in it. :slight_smile: Which I will post pictures of once I finish rebuilding the gunbox.

2

YOU TEASE!!!

You can’t make a post like that with out pictures! :walterpeck:

Seriously that is awesome. I’m doing my gunbox now too, and am planning on sanding down the curved edge. Might have to rethink that approach though after this.

3

I’ll post a pic tonight. I just have to go out shopping right now for parts for PKE’s I owe people. :slight_smile:

[edit]

Small correction on the measurements above. The wood I cut was 1 1/2" across the grain, not 1/2".

4

The best way I have made the round corner is using Hprop’s suggestion on his gun box templates,box the entire gun up,fill that corner with bondo,let cure,and then sand that corner down.You will need to do some light filling after that but I have not had a problem with that method at all.

5

seems like a lot of work..

6

I don’t know why people love Bondo so much.

It’s expensive because you can’t buy small amounts of it, it emits nasty fumes, it’s two part so you have to mix it, you have very little time to work it, and you have to either work it in with a stick or spatula, or with rubber gloves. Both of which will be ruined once you’re done one piece because they’ll have dried bondo stuck all over them. Then when the stuff dries, it’s hard as a rock, so it’s a pain in the ass if you’re planning to sand it by hand and you have to remove any significant amount of material.

7

What? Bending the wood, or all that sanding? Bending the wood is by far easier, and you don’t have to get covered in sawdust and bondo and use a loud vibrating sander for half an hour. :slight_smile:

8

Answered the question right there. Bondo basically hardens into a durable plastic which is great. Mixing time varies by how much hardener you add. Want more time, use less and vise versa. As for sanding it, start with a 60 grit then 80 then 100 then 220. The lower grit helps remove some of the nastiness that’s in the material due to spreading it on. Get your self a nice set of metal putty knives to use. Scrape the bondo off right after using while its still soft. Don’t let it fully dry on them and they’ll last you forever. even if it does dry, use a utility knife blade and a hammer to chisel it off. As for the bend itself. just get a 1-1/2" OD pvc pipe from the plumbing section , cut it in half and glue it it place. that’s what I did and it worked very nicely. Took all of about 10 minutes to set up and do.

9

But epoxy putty also hardens into a durable surface that can be sanded, and you don’t have to worry too much about getting it on your hands.

PVC is hard to cut by hand. And not everyone has a band saw. And if you only cut it in half, then you’ll have extra inside the gun body. And you’ll have to fill the gap that’s gonna be left at the bottom edge since you won’t be able to sit it flush on the wood. You need a quarter. That’s two cuts, the long way. Plus an angle cut. And to make those two cuts you’ll need to figure out some way to clamp it down to make those cuts without getting in the way of the cutting if you’re doing it by hand. Then you’ll have to take a file and file off all the shavings left over. In other words, cutting PVC is a pain in the ass.

Plus where are you even gonna get PVC that’s slightly larger in diameter than 1" PVC? 1 1/2" OD PVC is the same diameter as the handles. The curve has a greater diameter than the handle. Barring finding PVC with a 1 3/4" OD, you’re gonna be stuck using a coupling. And that’s gonna be a bit thicker than regular PVC, so harder to cut, and maybe not long enough.

Anyway, why would youy want to go through all that when you can simply cut a 1.5" length of wood, stick it in boiling water for 60 seconds, bend it around a pipe, hole it in place with rubber bands and let it dry overnight? That’s like 5 minutes of work, versus probably an hour to cut that PVC by hand.

10

Not all pvc is hard to cut. I got the tube in the plumbing section and had a wall thickness of about 3/32nd which coincidentally was the thickness of acrylic I used for the body. Also came in a 1’ length. My handles have an OD of about 1.25" which fits perfectly into the pipe I cut for the bend. As far as cutting it, I used a dremel and cut off wheel which ate through it like butter. to get the angle, i simply lined a ruler up with the angle on the side of the gun box and traced the line on to the pipe. Then used a dremel again to cut the angle. You can use a scrap piece of wood as a straight edge to make sure your line is nice and true. Any frays or extra pvc left on the pipe was sanded off with 60 grit paper. Never touched a file, never do.

It really wasn’t a hassle at all. As a matter of fact trying to locate the washers on a circle with rounded edges with nothing to square it up properly was a bigger pain. I guess the benefit to this method is it literally took 10 minutes while the bending method requires it to sit overnight. People in tight time constraints may not be able to wait that long, even if it is only a couple hrs. I’m not knocking your method I think its pretty creative especially if you have bass wood lying around.