Academy's styrene Vs. 3M's spot putty

I forget which brand I am using now, but I have used auto spot putty for several decades, including building several Academy kits.  I have never had a problem.  It is important to recognize that spot putty is indeed pretty hot, and to be sparing in its use.  The same thing is true with two-part fillers, which generate heat during their curing, though with spot putty the term hot does not mean a thermal reaction, but is a buzz word for chemical process.  With both types it is sort of like painting- better to do filling in several thin coats than one thick one.

Ditto on the spot putty. I used the "Bondo" blue for a long time but can't get it in this area anymore. Switched to the red. Used out of the tube, it's great on general filling. For the real small jobs, I have a small paint jar with the red thinned with lacquer thinner. Dries fast and sands easily.

Jim  

I can't answer you directly because I don't know any case where it was a problem. I've used Bondo Spot for about ten years now with no problems other than occasional craking of the putty if I apply it a little thickly.

One thing I do is mask my areas to be puttied to be close to the problem, and not apply it generally all over. I also don't use putty for chanbging shapes, mostly just for seam work.

Hi Gents,

Thanks for your thoughts on the subject. I think I may have solved my own problem. It seems as if the spot putty definitely reacted with Academy's styrene in a different manner than I'm used to. It appears as if Academy's styrene is a little softer than I'm used to. It was really "hot" and softened the plastic. I wasn't waiting long enough between application and sanding. The styrene was still soft and reacting with the putty. I tried it on a scrap piece and let it sit overnight with no ill effects. Lesson learned.

Thanks for all your input. It's much appreciated.

Cheers,

Greg

Greg;

       I have found that the use of " Spot " putty is directly opposite to what is intended . In the auto Body world it is Not used till the surface has been primed and then sanded Showing the low spots .( Rock and stone divots and door bumps ). I would insist that unless there was no other way then use it sparingly ! T.B.

Tanker - Builder

Greg;

       I have found that the use of " Spot " putty is directly opposite to what is intended . In the auto Body world it is Not used till the surface has been primed and then sanded Showing the low spots .( Rock and stone divots and door bumps ). I would insist that unless there was no other way then use it sparingly ! T.B.

 

Note that many brands now call it glazing putty vs spot putty.  Also, I generally prime before filling a seam, and only use the putty when the seam has low spots. I file off high spots.  So I am in effect doing the same thing with it as when I use it on a car body.  

I do agree with the idea that it must be used sparingly.