Removing Mold Lines From Polymer?

[commygun]

So probably not terribly technical but I don’t want to make anything unsightly. Does anyone have any tips on removing the mold lines from polymer frames without discoloring or abrasion marks. Any tips on the best grits and techniques would be appreciated!

 

[Tilos]

I have had good luck dragging a single edge razor blade over the mold lines (seams).
I have even bowed them for curved surfaces and still works on flats.
And I finish up with sanding but most times scraping is enough.
Bow it like this:

Drag it at an angle, in this direction:

works for me,

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[deadeye dick]

You could try some wet- dry sandpaper in the micro grits. Works on car paint and bondo. A 2000grit will probly polish it or coarser grits will make it duller.

 

[Mizar]

Plus one on the razor blade. The small blade of Victorinox SAK also works rather well.

 

[MikeInOr]

I would also go the razor blade / Xacto knife approach to cut off the flashing.

If you are really adventurous and want a really smooth finish you could use a mini butane torch to smooth out the flashing. But I don't think I would have the guts to.

 

[Tilos]

I would also go the razor blade / Xacto knife approach to cut off the flashing.

If you are really adventurous and want a really smooth finish you could use a mini butane torch to smooth out the dlashing. But I don't think I would have the guts to.

Especially if it has the serial number attached to that part.
Replacement could get pricey.

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[Ohen Cepel]

I have done the razor blade and touch up with a bit of sanding also. Not hard to do and with a little use you won't even notice it unless you really messed it up.

 

[ddc]

For Sig P320 plastic it is fairly straightforward to end up with a finish that is indistinguishable from factory.
(Assuming we are talking about the smooth portion of the grip and not any area with texture.)
That involves the use of progressively finer sandpaper once the initial material has been removed.
Of course those grip modules are not the serialized portion of the gun and are easily replaceable if something goes wrong!

 

[BWS]

One method we use on certain furniture color sticks....

Find a 3/8 or 1/2" wood chisel you don't care if it gets ruined,consider it dedicated to this application. With a std propane torch running,heat the business end of the chisel and use it to melt in the lines. It's also good for stock work,with the aforementioned color sticks. In use it's like an old school soldering iron.

I leave mine with the finishing supplies,always there. DON'T use your good chisels for this!

 

[rust collector]

I use a thin snap-off blade to remove flash, and then burnish with a wooden dowel. Next step, if needed, is 220 or 400 grit wrapped around the dowel.