Fillets

I use sig epoxylite for my fillets. Every once in a while I get the little bumps that everyone knows about. I read somewhere a while back about putting one of the parts in the microwave for a bit before using it. Can anyone refresh my memory on this.

I know the perferred choice of material now is Aeropoxy lite. I actually used some to make a perfect cowl fit. Very nice stuff. I am going to use up my sig though. Three reasons. I can get great fillets with it. I have alot of it. My local shop is out of the other stuff.

If anyone can help I would be greatful.

Doug Moon

Put the brown part in the microwave for just a couple of seconds and it will liquify the lumps. I like Epoxolite for fillets myself, especially for profiles. I really do not think Aeropoxy is as strong..

There are two things that cause the "bumps".

The main one being that it is beginning to gel while you are working with it. Only mix enough to do ONE fillet run. That's across the top of a wing only or across one stab fillet etc. You should be able to complete them one at a time with a fresh mix each time and have no bumps appear. If you try to do more than one per mix you will run into trouble.

The other reason is the stuff is just getting too old. It does seem to have a finite shelf life.

When it comes to Aeropoxy lite which is my preferred choice, be sure to frequently turn the brown part B container over. The "filler" or "body" floats out of the epoxy base otherwise.

I believe Tom Dixon had the artical in Stunt News a year or two ago about the epoxolite material and heating it up, Bob was right about heating it up to make it smoother. I found it also works to revive an old batch of epoxolite that has gotten stiff in the container. Also heating makes it a bit thinner so as to make an easier application,(less friction when applying).

>I use sig epoxylite for my
>fillets. Every once in
>a while I get the
>little bumps that everyone knows
>about. I read somewhere
>a while back about putting
>one of the parts in
>the microwave for a bit
>before using it. Can
>anyone refresh my memory on
>this.
Put the two parts in the microwave for 10 seconds (separately). This will make the parts smooth like melted peanut butter. This is, by the way, the same technique I use for Bisonite, a steel filled epoxy I use for bedding rifles (little known trivia). Not invented by Tom Dixon, but a reminder always helps.

I have a few tips about Epoxolite that may be of interest to a few of you. First, using the microwave to rejuvenate the Epoxolite works like a champ but never mix the two parts together when they are still hot. The pot life (working time) is reduced to about half.

Second, use masking tape to outline the area where you want to make a fillet and use your finger to press the Epoxolite into the joint. Use a 5/8” deep socket to shape the Epoxolite into a perfect fillet. Dip the deep socket in methanol or rubbing alcohol to keep the Epoxolite from sticking to the deep socket. Remove the masking tape and feather the edge of the Epoxolite down with a rag dipped in methanol or rubbing alcohol (the methanol works the best). Allow this to dry for 24 hours and sand with 150 grit sandpaper (nothing finer).

Third, apply three coats of nitrate dope (brushed) onto the fillets only. Lightly sand the nitrate dope with a fine 320 grit sandpaper. Be careful not to sand off the nitrate dope.

Finish painting the model as you would normally do, only try to keep as much paint off the fillets as possible. I have used Epoxolite for years and have never had a problem with lifting fillets.

One note of caution here is to never use model filler over the top of Epoxolite to smooth out a rough or imperfect fillet. This will cause the biggest blister that you will ever see. I had to grind out the MM filler and redo the Epoxolite fillet. One other hint that I will pass along about Epoxolite. It is really easy to carve Epoxolite at 2-1/2 to 3 hour after it has been mixed. This is really handy to know when making a special shaped part that requires additional shaping and/or a little carving before the Epoxolit is fully cured.

I hope this helps,
Mike

Thanks for teh replys. I am sure it will help reduce the bumps.

Doug