Hey, I'm dying here! My canopy, that is

This kind of surprises me since I've had modest success with RIT dye in the past. Anyone got any shrewd ideas? Thanks in advance.

Champ:
From past experience I can suggest something NOT to do.

1) Trying to use a microwave to speed things along isn't really as smart as it may seem.

2) Although the dye seems to have absolutely no effect on the canopy, even when soaked for a week or two, exposure to a carpet (or socks / pants) takes only a nano-second to be very noticable.

See Ya

I think the key is to heat it to a pretty warm state. Not enough to distort the canopy but hot enough to creat a little more room between the molecules. somewhere about 115-125 degrees I believe would get the job done. Hope the "Special" flies as good as I know it will look!

Walter:7

We haven't used butyrate plastic for at least 10 years, maybe more. If you successfully dyed a SIG canopy in the meantime, you had one that was old stock.

Bottom line is PETG will not accept dye of any sort that we have tried.
On the plus side, PETG is a lot tougher and doesn't get as brittle with age as butyrate plastic, not to mention that it molds easier on our end.

Mike Gretz
SIG Mfg. Co.

Of course, Ted made his own canopies from what was labelled SIG Butyrate sheet - so unless the material was labelled incorrectly, these were butyrate.

Well, not exactly true, Brett. I went to the hobby shop and bought Sig plastic just like I've done in the past. It looked the same but came in sealed plastic envelopes. I'll have to go smell it. The old butyrate stuff smelled a bit like vomit...sorry. If this stuff doesn't stink it is probably what Mike says it is.

I'm going down to the garage to check it out.

OK, here's the story. If I had taken the time to read the labels I would have found out it wasn't the old stuff which came from (I think) SIG. This stuff comes in a pretty plastic package with Red, White and Blue labeling that clearly says K and S clear plastic on it. It does not specify what kind of plastic it is but it doesn't stink like the stuff I'd used before.

After several hours in a plastic jug full of dye sitting in my crock pot it has taken on a very modest amount of color. I've plugged the crock pot into my dremel tool rheostat to reduce the output a bit and will leave it to cook all night and, hopefully, not distory with the heat.

I apologize for the mis-information in my original post.

>OK, here's the story. If I had taken the time to read the
>labels I would have found out it wasn't the old stuff which
>came from (I think) SIG. This stuff comes in a pretty
>plastic package with Red, White and Blue labeling that
>clearly says K and S clear plastic on it. It does not
>specify what kind of plastic it is but it doesn't stink like
>the stuff I'd used before.
>

My mistake. Pretty tricky - same package, different material, huh?

>OK, here's the story. If I had taken the time to read the
>labels I would have found out it wasn't the old stuff which
>came from (I think) SIG. This stuff comes in a pretty
>plastic package with Red, White and Blue labeling that
>clearly says K and S clear plastic on it. It does not
>specify what kind of plastic it is but it doesn't stink like
>the stuff I'd used before.
>

I think what this really says is that K&S has made the switch to PETG also. Most people have. And not just recently. This switch has been going on for many years.

The packaging industry (vacu-formed blister packaging of everything from wiper blades to food) undoubtably uses the largest quantities of clear plastic sheets in the world. When they began making the switch to PETG (PolyEthlene Terephtalate Glycol) when it came out, the older plastics (plain Acetate or CAB-Cellulose Acetate Butyrate) slowly fell by the wayside. CAB (butyrate) plastic sheets are actually getting hard to find. Obviously, the plastic manufacturers are going to cater to their largest customers, the bulk users, and focus most of their production on PETG. Thus the cost difference between PETG and CAB keeps getting wider.

I remember the first time a manufacturer's rep came into Sig and told us about this new clear plastic called PETG. I think it went something like this;

"PETG is a transparent copolyester with very high impact resistance. Tough, clear, versatile, easy to work with, and chemically resistant. Maintains exceptional clarity during fabrication, heating and vacuum forming without whitening. Surface scratches and scuff marks can be removed using a common heat gun. Ideally suited for a variety of demanding sheet and glazing applications ranging from store displays to signage. Meets all current food contact legislation, so it can be used in contact with food. And best of all it costs about 2/3 as much as the CAB sheets you've been using. Let me leave you some samples to try forming some parts."

Well we tried it, we liked it, and it's been working great for many years. The only thing it didn't do BETTER than butyrate was the dyeing issue. It didn't take dye worth a d*#n. "In the old days", SIG sold all our aftermarket and some kit canopies in 3 dyed colors in addition to basic clear. There was a regular household stove up in the kit department, with a large flat homemade sheet metal pan that laid across all the burners. Into the pan went the water and powdered RIT dye, and when it was hot enough, you dipped in the whole 17"x17" plastic sheet. This was done before the canopies were vacu-formed. We tried using the same process with the PETG, and it didn't work. Since the dyed canopies were really not a large seller, they were simply discontinued.

As butyrate plastic has become less available, the price difference between it and PETG has widened. I just did a quick search on the internet and found these prices from one plastics distributor (it took a while to find one who still handled both types):
CAB Sheets ... .030 x 22" x 51" ... $40.36 each
PETG Sheets .. .030 x 24" x 48" ... $12.00 each
PETG Sheets .. .030 x 24" x 48" ... $16.00 each

The bottom line is that we sometimes have to adapt to the newer stuff. In this case, I personally have no doubt that PETG is the better plastic. It's a lot tougher and ages better than butyrate.

From the good responses this thread got, it looks like a lot of guys have worked around the issue by tinting their canopys with paint instead of dying them. I know that's what Mike Pratt has done on some of the stunters I've seen him finish here at Sig. I'm surprised to hear Doug Moon say that he has had no problem dying new Sig canopies with Rit dye. It didn't work very well for us. Maybe we didn't get the temperature high enough.

Please let me know what you find works best for you Ted. You're not the type of guy that normally settles for "good enough".

Mike Gretz

That last line in the pricing list should have been:
PETG Sheets .. .030 x 48" x 48" ... $16.00 each

Also, did you notice where the manufacturer's descriptoin said that scratches could be removed with a common heat gun? Haven't tried that myself, but I think what they are saying is that the scratches will actually close back up and fuse together, rather than split wider apart. Obviously there is going to be a FINE line between the temperature to do that and the temperature that will melt the shape of your canopy. Nonetheless, it's something to keep in mind if you get some small scratches in your canopy that you just can't live with.

I had pretty good luck on my Cessna 172 windshield with 1500 wet-or-dry followed with Maguires polish.

Should I try this on the SIG canopy, or will I end up with a worse mess?

Jim Hoffman

The method that I have used on the last few planes consist of applying tinted clear dope or clear automotive lacquer on the outside of the clear canopy , sanded with 1000 grit fine sandpaper .

After all of the color finish is applied to model , I mix clear dope or lacquer with a few drops of black paint mixed in ,Any color will work ( Candy Colors OK ). Adjust the amount of color to get the correct tint that you desire . Apply this color tinted dope/lacquer to the taped off CANOPY ONLY. You can airbrush darker tinted clear to get a darker area on different parts of the canopy if desired. Use 1000 grit fine sandpaper to clean up the edges of canopy tinted clear.

Clear cote the entire model as normal.

Advantages.. You can decide on color after your model is completed, You can retofit tinted canopy to older plane, better blend line at canopy.

Disadvantage.. You can only use this method on canopy with clear coated finish, You can melt a canopy with too much clear or too slow thinner,

William Davis

If I want a solid color I do like Richard and spray paint the inside. Except I use a flat matte color, spray paint from the local hardware store 1.95 a can, and it shows through as a gloss and it is very even. It has worked on all the Canopies I have tried but one of the ARF Nobler Canopies. It did take on the other ARF Canopy so it either had something on it or the paint wasnt good and shaken up in he rattle can. I did it this way for years before I tried dying.

Good luck and let us know how it turns out.

I'm going to be trying some of the assorted tricks while doing other chores on the airplane. When I finally get something to work I'll pass it on.

FYI, thanks to advice from Randy Smith among others (thanks for the call Randy) I heated the dye solution and this seemed to make all the difference. Got a good clean and clear color change that appears to be just right. According to Randy the temp has to be within a narrow range between too cold to do the job and so hot it distorts the canopy, somewhere around 180 degrees fahreite.

I used my little $10 Crockpot and it seemed to work just fine. It has a single setting that heats the water to something below boiling. Just to be on the safe side I used my Dreml Tool rheostat to vary the voltage and started just a little off max. Eventually found I could go all the way to max and left the canopy in the mix overnight. I'll get an actual temperature reading later and add that info.

By the way, the crockpot isn't big enough to get the canopy in, so here's what I did to solve that problem. I have a one foot tall round plastic container that came from Costco with about a zillion tie wraps. I put the actual dying solution in the tall container and placed it in the Crock pot (along with the water in the crockpot which is the medium for transferring the heat.) This has worked fine.

Ha, ha, Howard. What is interesting is that the clear plastic container seems impervious to the dye! dum-de-dum-dum.

I measured the temperature of both the water in the crock pot (in which the dying container sits) and the dye itself ... only about a third or a little more of the dye container is actually submerged in the crock pot medium. The crock pot gets to 135F and the dye to 120 or so. This should be well below the temperature at which the canopy distorts from the heat. The dye transfer is so good I see no reason to use warmer temperatures which might risk such distortion.

Thanks to all for your inputs.

See, I told you about 120 degrees or so!

I too have come upon this task in the construction of my new Mustang. In the past I have heated the water, added the Rit dye and waited...and waited...and waited only to see a microscopic change in color. I have heated the water hot enough to warp the canopies as well, but with limited success.

So with trepidation, I launched into this task on this plane, with one exception.......SALT. WOW...Within one hour at 130 deg F, the canopy is darker than I have been able to get in years. It is the same SIG WWII canopy from Brodaks that I have used for the other 2 Mustangs. The only difference here was the salt. It worked great!!!

Thanks for the tip Colin!

PAUL,
CAN YOU TELL IF THAT CANOPY IS BUTYRATE??

NO......IT HAS NO DESIGNATIONS ON THE LABEL. I OPENED UP ANOTHER PACKAGE CONTAINING A LIKE CANOPY ANS THERE WAS NO, I REPEAT NO SMELL THAT MY NOSE COULD PICK UP.

THESE APPEAR TO BE THE SAME AS THE ONES LAST YEAR THAT DID NOT WANT TO TAKE THE DYE. THE ONLY DIFFERENCE IS THE SALT!

p.s. Are you to color paint yet? What colors are going to be in this one? I really liked your Intimidation paint scheme from a few years ago. Hope the new one is flashy like that one!