Best Way to Plug Holes in a Semi Truck Frame?

[Jim B]

So, I am working on an AMT "Part-Box Special" Chevrolet Bison I got several years ago, and I am making some modifications to it.  Namely I am not using the stock fuel tanks & such.  What it the best way to plug all of the holes that are in the Bison frame?  Some of them are pretty big so I don't think putty is the best answer.

Thanks.

Edited January 31, 2024 by Jim B

[slownlow]

How big is “big”? In some cases a plug can be made from the kit’s sprue. Some shaving to match the right size may be needed. Another technique is to make “sprue glue”. Cut up small chunks of sprue and add what ever solvent glue your using. The plugs will dissolve and form a paste which can be applied to the hole. After drying the patch can be sanded to match the piece. There are also 2 part epoxies on the market that will also fill areas. My favorite is Milliput extra fine. Which ever way you choose good luck.

[Fat Brian]

Pieces of sprue or scrap plastic glued in with plenty of liquid glue will make a good, strong patch that you can then sand smooth with a bit of putty.

[NOBLNG]

If they are smaller than the diameter of the sprue, I would heat and stretch a piece of sprue. This will give you a tapered piece that can be pushed snuggly into the hole regardless of the hole size, and then glued with solvent cement (my preference) or CA. Once dry the ends can be trimmed and sanded flush.

Edited January 31, 2024 by NOBLNG

[Skip]

The old Go-To method of using some sort of styrene rod to plug the hole has always worked here.

I've always used either Evergreen Styrene Rod or stretched sprue to fill those types of holes, I think it goes clear back to the Model Car Science Magazine days where maybe Don Emmons or one of their other contributors demonstrated it in a sidebar to another article.  It has also been discussed in both Fine Scale Modeler and SAE as a method to close up holes in styrene and resin.

Here's how I normally close up a hole in a styrene part. - 1. Brush liquid glue into the hole.   2. Insert Styrene Rod or Stretched Sprue into hole(s).  3. Allow glue to set.  4. Trim excess flush to the top and bottom surfaces with either an X-Acto knife or sprue cutter - (the flusher the cut off the less overall sanding will need to be done), sand, fill with appropriate filler, sand again, prime, paint...  Most of the time very little, if any filler will be needed, if it is required a tiny dab of thick CA glue on top of the filled hole should suffice.

[Jim B]

21 hours ago, slownlow said:

How big is “big”? In some cases a plug can be made from the kit’s sprue. Some shaving to match the right size may be needed. Another technique is to make “sprue glue”. Cut up small chunks of sprue and add what ever solvent glue your using. The plugs will dissolve and form a paste which can be applied to the hole. After drying the patch can be sanded to match the piece. There are also 2 part epoxies on the market that will also fill areas. My favorite is Milliput extra fine. Which ever way you choose good luck.

The biggest ones are for mounting the fuel tanks & battery boxes.  One set is 2.5mm x 6.5mm and the other set is 2mm x 7mm (give or take a little).

Thanks for all your tips, guys. I appreciate the help.

[NOBLNG]

23 minutes ago, Jim B said:

The biggest ones are for mounting the fuel tanks & battery boxes.  One set is 2.5mm x 6.5mm and the other set is 2mm x 7mm (give or take a little).

Thanks for all your tips, guys. I appreciate the help.

I would make a slightly tapered wedge piece from sheet or rectangle stock so it can be pushed into the hole snuggly and glued, then trimmed.?