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Dealing with Warped Resin Parts

sharkmouth

Information Overload
Staff member
Many times a kit which has been stored will become warped. Whether at the stockist or in your stash, pressure or temperature may cause thin long items to warp.

Here are some thin resin Panzer 38 (t) sprockets that were deformed during shipment. The inset shows them after a dip.


The technique is simple and based on the principle that resin has memory. If the manufacturer allowed the resin to fully cure in a true and level mold, the resin will return to the shape it had in the mold if given the opportunity.

I usually boil water and put it into a clear container so I can see the effect of the heat. Here I am using a Pyrex measuring cup as my normal coffee press jar is too unsightly :woohoo:


Note that one must hold the item by the carrier sprue. In the case above, this was not a good idea as the warmed up resin sprocket began to deform from the weight of the water. I had to hold one of the fins between the sprockets and re dip it.

The idea is to dip the item into the water slowly and watch it relax into the proper shape. This means that the item can not touch any of the sides or bottom.

After the proper shape is regained, slowly remove the item from the hot water and dip into cold water. After it is in the cold water, it can be placed onto a towel to air dry.

Here we have Tank Work Shop's British Style Wading Kit as it came out of the package. I did NOT remove the casting blocks and used them as a handle to dip them into the hot water.


Post dip, note the water droplets still on it:


Here is a severely warped Marder II interior:


As you can see, I dipped it twice since I removed it too fast during the first one.

This has worked on EVERY warped item I have except for an Eastern European one which I suspect was warped in the mold. I have straightened out items as delicate as the above to thicker hulls (which warped under pressure).

The bottom line is to NOT touch, push, prod, the piece and allow it to regain the original shape on its own. Believe me, it's memory is a lot better than you can do when it comes to straightening out gun barrels!

I hope this quick tip is of help.

Regards,
 

chukw

Active member
Well. I'll be bloggered! Thanks, Saul- I'll be sure to use this strange new power only for good- cheers!

chuk
 

Iron Mike

Master At Arms
Staff member
Well, the first attempt worked partially. Here's what I started with.






After a really hot bath, followed by a polar plunge.




Going to run it again as there's still a little bend to the barrels.

It's good to have smart friends. :notworthy
 

iambrb

Well-known member
Neat stuff! Hey I have a questions, as I am not that familiar with the thin-gauge resin castings, like that wading kit. To me that look terrible! Is it standard far a manufacturer to send out product that looks that bad? or does it warp in transit?
 

sharkmouth

Information Overload
Staff member
Going to run it again as there's still a little bend to the barrels.

It's good to have smart friends. :notworthy

The polar bath is only to continue working on it. For that to happen, one must be real careful removing it as the parts are soft and bound to bend under their own weight. If you are not in a rush, leave it undisturbed until the water reaches room temperature (meaning the resin is also as hard as you normally would handle it) This ensures plenty of time for the heat to travel through the resin and it returns to the shape it was in the mold.

Are these Live Resin barrels? They look familiar.

Neat stuff! Hey I have a questions, as I am not that familiar with the thin-gauge resin castings, like that wading kit. To me that look terrible! Is it standard far a manufacturer to send out product that looks that bad? or does it warp in transit?

No, TWS normally doesn't send out anything in that shape (I don't recall any). This is from storage.

Regards,
 

Iron Mike

Master At Arms
Staff member
My parts are from Legend. I will give it another go. It should be noted, my clip severely mashed the heated resin (full Homer Simpson mode ensued), but another hot bath relaxed it back to original shape. No kidding.

B)
 

Heavens Eagle

Well-known member
I have a Silver Wings 1/32 He51 float plane that came with the fuselage and both floats showing a slight curve to them. The part halves are taped together at the factory and shipped. The sides match and they are rather heavy parts.

I also do my water bath in a 10 x 13 cake pan. Set it on the stove and warm it up. I use a meat thermometer held in place to monitor and regulate the temperature of the water. I have found 180 to 190 degrees F to work fairly well with plastics. Dip, stir it around a little, then pull out and flex it to correct shape by hand. I have done this with resin as well. Hotter water or too long and immersion "WILL" make plastic parts SHRINK! (and do all kinds of other nasty things) Not sure with resin, but I would be hesitant to overdue the process.
 

sharkmouth

Information Overload
Staff member
I also do my water bath in a 10 x 13 cake pan. Set it on the stove and warm it up. I use a meat thermometer held in place to monitor and regulate the temperature of the water. I have found 180 to 190 degrees F to work fairly well with plastics. Dip, stir it around a little, then pull out and flex it to correct shape by hand.

I agree with it all except the flexing by hand (for resin) as it has a better memory to return to the shape it was in the mold than you can with manual dexterity.

Regards,
 
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