Bondo for shaping a patch box ?

[ptk1126]

I have been having a little problem shaping parts of a patch box to the profile of the stock.

This is the patch box


I know many members have discussed using bondo to hold parts. My thought is to
put a layer of bondo on a flat piece of wood and press the appropriate part of the stock
into it. Then, there should be an accurate profile of the stock to use to shape the patch box.

What should I use to prevent the stock from sticking to the bondo ?  Suran wrap, wax paper etc ?
Will those materials adhere to the bondo ? Will the bondo stand up to light tapping used to
shape the box ?

Thanks for your advise.
Paul

[moleeyes36]

In the interests of full disclosure  , I've heard of this technique from others but have never tried it.  My thought is that a piece of plastic wrap stretched over the stock would allow the Bondo to take the form of the stock.  If it did stick to the Bondo it is so thin it doesn't seem that it would make a difference in forming the brass to the cast impression in the Bondo.  I'd just be concerned that the Bondo doesn't make contact with the bare wood or things could get interesting indeed.

Mole Eyes

[rich pierce]

Paul, will you cut a groove in the bondo for the hinge then pound the patchbox down into the form with a rawhide mallet or what's the plan?  Will you use screws to pull it down also?

I'm having a time getting a large surround patchbox fitted. So thanks for opening discussion.

[Scota4570]

To get a curve that fits the stock you will need to bend the metal in a smaller radius form than the final curve.  There will be some spring back.  I make forming dies out of wood.  I push the metal in using a hydriolic press.  I also use a big fat dowel in the curved form.  Beating the metal directly with a hammer will not work as well.  You'll make dents, and curve the metal in more than one dimension.   

[tallbear]

I think you would be better off rasping/filing out a depression in a block of wood that is a little more curved than your stock.Due to spring back in the metal I've always found I need to over bend the parts a little so they better  fit the stock rather than having an exact stock profile.

Mitch

[Mike Brooks]

Anneal brass. Dig a trench in the wood where the hinge is. Screw box to stock. Trace around box.  Remove. patch box is now bent to the profile of stock. Inlet box until flush with stock. Screw box down yet again.  File stock and box together until flush. Notice you have filed 1/2 of your nifty engraving off of the box. Consider engraving box AFTER inletting in stock from now on. Leave doodad inlay forward of the box off of the gun.

[Curtis]

I recently did a four piece box and resorted to using whatever I had on hand to form the box.  Normally I would just use the stock as per what Mike said, but the wood was very soft and the screws would not take a lot of stress before pulling out.  Also I was afraid of severely denting the wood if I had to pound on the brass to shape it.  I also second Mike's thoughts on engraving the box AFTER it is inlet in the stock.  Here are some pics of me forming the finial and lid, using a pistol stock blank and a mallet as forms:
















If you don't have anything in the shop suitable for forming it already, I think the Bondo idea would work, and certainly making a form from hardwood would work as well.

Curtis

[David Rase]

I form my boxes using the actual stock.  Once I inlet the hinge I use a combination of vise, vise grips, flat nose pliers, swage block and hammer to bend and shape the patchbox and then keep est fitting it over the stock until it follows the contours.  I have found no need to spend the time making additional forms etc.
David

[Mike Brooks]

You know, 1/2 of the guys on here say a curved hinge won't work, so you might as well start over.

[rich pierce]

Mine is 1/16" thick and making me nervous but I better man up and get to it.

[flehto]

I first use a tracing to position the Pbox on the stock and then use an awl at points that will locate the actual Pbox. The first piece of usually 4 pieces is the finial and it's screwed down according to the "awl" marks using a center screw if there is one, otherwise some other screws  are used. A soft mallet pounds the annealed finial to the shape of the stock. The 2 side plates require no forming. so that leaves the lid which I form on a separate wooden block made from a pine 2X4.

The hinge pin made from 1/16 dia baling wire is bent to conform w/ the curved hinge....Fred
 

[Daryl]

I don't know how Taylor did this one - but I know he uses bondo when engraving.

[Hemo]

I recently did a four piece box and resorted to using whatever I had on hand to form the box.  Normally I would just use the stock as per what Mike said, but the wood was very soft and the screws would not take a lot of stress before pulling out.  Also I was afraid of severely denting the wood if I had to pound on the brass to shape it.  I also second Mike's thoughts on engraving the box AFTER it is inlet in the stock.  Here are some pics of me forming the finial and lid, using a pistol stock blank and a mallet as forms:
If you don't have anything in the shop suitable for forming it already, I think the Bondo idea would work, and certainly making a form from hardwood would work as well.

Curtis

I hope that nice curly pistol blank didn't sustain any damage during its use as an anvil!

Gregg

[oldtravler61]

  If you look at Curtiss patch box an the other's. You will see a curved hindge will work.
 No expert but the few I have made had no trouble.
Just filed a little bit on the bottom of the door hinge to make it work.
  You won't see the difference anyway cause it's faced down from you. 
  Just the way I do it. Maybe not the best way but it works. An have never had anyone notice.  Oldtravler

[T*O*F]

If you can squash a tin can with your thumbs and index fingers, you can bend a patchbox.  I don't know what all the ado using forms and other paraphanalia is all about.....especially Curtis with those big guns he's got.

[Mark Elliott]

I use the following form to bend my patchboxes.    I anneal the parts of the patchbox and then press them in between the forms in a vise.   That does not impart the final curve.   I inlet the parts screwing them down to the stock during the inletting.   This will form them to  the stock.  I also use a small plastic head fitting hammer to hammer down stubborn edges.   You may have to anneal the parts a couple of times during the bending and fitting.  Once everything is inlet and screwed in place,  I file everything down even to a #2 swiss.   After that, you can polish and engrave.   

I should note that you have to bend the hinge before you fit the lid and finial together.    I do bend the hinge.   It just isn't bent as much as the rest of the lid and finial.   

Additionally,  the curve in the form is greater than the normal curve in the stock.   It is the only way to bend the lid and finial enough.   You can always spread the finial a little bit when you screw it down.   I don't worry too much about the bend in the sideplates as they are usually to narrow to have much bend in them.   You can usually inlet them flat and file the edges.   

I use 1/16" thick material for my patchboxes.  So,  there is plenty to file. 


 

[ptk1126]

Thanks to all for the comments and suggestions.

This is my fourth rifle but first with such a complicated patch box. I think I got a
little cocky and overestimated my abilities.

This is a copy of a box by Nathan Clause on a rifle on display at the Frazier Museum in Louisville (picture
attached).



The box and nearly all the furniture are attached by small brass or silver nails so
I don't see a reasonable way to use screws to form the box to the stock.

Mike - I sure did make it difficult by engraving before inletting.
Never again !!  Unfortunately, the "doodad" at the end has to stay.

Mark & Mitch - Thanks for pointing out the need for the form to have a greater curve
than the stock. I had overlooked that.

I think I will go ahead and give the bondo a try.

All the best
Paul

[Mike Brooks]

Ah, I see that gun is from the "doodad"  school.....  Better keep that doodad on there I guess.

[deepcreekdale]

Just an aside. If you want to use  Bondo to support pieces while engraving ( I usually, if not always engrave after the piece is installed) after completion of whatever you are engraving, just heat the brass up with a torch. You only need to get it warm and it will pop right off with no residue remaining on the brass. I have never used Bondo as any sort of mold material for bending parts. I don't know how well it would work, it is not all that strong unless it has glass cloth in it.

[Curtis]

I hope that nice curly pistol blank didn't sustain any damage during its use as an anvil!

Gregg

Gregg, the pistol stock was good as new after my little abuse session....  good hard curly maple on that one!

If you can squash a tin can with your thumbs and index fingers, you can bend a patchbox.  I don't know what all the ado using forms and other paraphanalia is all about.....especially Curtis with those big guns he's got.

Very true, TOF, however the current use of aluminum for beer cans (as opposed to tin) has made me get soft and weak!   
I also used 50 thousands brass for the box, made it pretty stiff even when well annealed.


Curtis