Thinning Gelcoat with Acetone - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  Thinning Gelcoat with Acetone

search | FAQ | profile | register | author help

Author Topic:   Thinning Gelcoat with Acetone

Wanchese posted 02-28-2005 04:04 PM ET (US)
The Spectrum gelcoat instructions used to state that gelcoat could be thinned with acetone; however, now they say that acetone is NOT recommended, and one should use styrene monomer instead.
Has anyone had any problems using acetone? Is this just a marketing thing so you will buy the styrene monomer at $17.78 per quart.
I note that Tom W. Clark used acetone for the major repair in "Repairing Hull Damage the Whaler Way."
Thanks for any and all input.
keltonkrew posted 02-28-2005 07:00 PM ET (US)
I used acetone in my re-do....that's what I was told to use by LBI Fiberglass....although a lot say don't use it...I went with the manufacturer's instructions.
Taylor posted 02-28-2005 07:42 PM ET (US)
Acetone from Fiberlay is eight bucks a quart, so the difference is not all that much. Yeah, I'm cheap - but when it comes to materials for a job like this, I don't scrimp. The cost savings is in doing the labor yourself.
If the directions had said 'styrene' that's what we would have used. When I exchanged email with Spectrum Customer Support last year they said that gelcoat formulations had changed since I did my repair and thus their instructions had changed.
There is some discussion of this in the follow up thread to the repair article: http://continuouswave.com/ubb/Forum3/HTML/003090.html
Tonym posted 02-28-2005 09:09 PM ET (US)
Some people also recomend a good laquer thinner to cut gel coat. Tonym
bdreaper123 posted 02-28-2005 10:01 PM ET (US)
I used Acetone to thin my gel coat. That was what my instructions said to do. I would do what ever the manufacturer recommends.
Martman posted 03-01-2005 08:12 AM ET (US)
Wanchese,
How much do you need? I purchased a gallon when spraying one of my 13' last fall. I still have at least 2/3 left. You are welcome to have some. Just email or post here.
Marty
Wanchese posted 03-01-2005 11:50 AM ET (US)
Hey Marty,
Thanks for the offer. I figure I need about 4 ounces or less.
Hey, didn't I look at one of your boats about this time last year in Wilmington? I bought an old Nauset. I don't have your e-mail. I'll leave mine here. Drop me a line and we'll get together.
Thanks,
John
stevensj@uncw.edu
John O posted 03-01-2005 09:50 PM ET (US)
Hello Martman,
I will be in Wilmington in a couple of weeks for a little R&R and could use a small amount of gel coat myself. I would be happy to pay you for it.
Martman posted 03-02-2005 08:14 AM ET (US)
John O,
I have some white (generic) gel coat and a little 1950-1972? color off white spectrum gel coat. Drop me an email on your schedule.
Marty
John O posted 03-03-2005 07:11 PM ET (US)
OH, I was looking for Desert Tan. thanks anyway. I will be in Wilmington 3/17-3/20
SMLWhaler posted 03-11-2005 02:30 AM ET (US)
I used Spectrum product on the inside and outside of my 13 with excellent results. I followed their recommendations and purchased 1 quart of Slo Patch for every quart of gel coat. Worked like a charm. Kicked the way it was suppose to, ended up with a nice job. I would use what the manufacturer dictates. If it costs a little more, so what. You won't have to contemplate a redo because you took the cheap route.
If I remember correctly I used 3 quarts of gel inside and 3 quarts outside. As previously stated you need 1 quart of Slo patch for every quart of gel. Its expensive no doubt. Finished product will be an accurate color match and very durable.
gtcway posted 03-11-2005 05:56 PM ET (US)
SMLWhaler, was that 3 quarts total on the inside or 6 when mixed with the slowpatch? I'm thinking about doing my 15' whaler this summer.
SSMarine posted 03-11-2005 09:57 PM ET (US)
Thinning gel-coat with acetone is not a good practice, overthining will cause problems with curing, also my experience has been that acetone changes base gel-coat colors. My best results have been with Dura-tec High gloss additive, 50/50 with gel-coat, thinned if neccessary with
M.E.K. Solvent and catylized 2% (14 drops per oz.) M.E.K. hardener. The Dura-tec does not require an addition of a surfacing agent (wax) or application of P.V.A. to get a hard, tack free surface. Dura-tec also makes your gel-coat go alot farther as you mix it 50/50. Be advised that Dura-tec, like gel-coat and other surfacing agents have a fairly short shelf life. It seems most gel-coat applicators have a "recipe" that works best for them, for me this works best!!
SSMarine posted 03-12-2005 08:43 AM ET (US)
P.S. one important note on thinners, (any thinners)
never thin gel-coat more than 20%. Color change and
non-hardening almost certain. Personally don't find it
necessary to thin more than 10% to shoot gel-coat with airbrush or HVLP gun. Improper hardening is usually related
to too much thinner, incorrect hardener ratio, too low of
temperature, or using a laminating gel-coat without wax or a surfaceing agent,or not covering with PVA. Hope this helps!!

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: Thinning Gelcoat with Acetone
Wanchese	posted 02-28-2005 04:04 PM ET (US) The Spectrum gelcoat instructions used to state that gelcoat could be thinned with acetone; however, now they say that acetone is NOT recommended, and one should use styrene monomer instead. Has anyone had any problems using acetone? Is this just a marketing thing so you will buy the styrene monomer at $17.78 per quart. I note that Tom W. Clark used acetone for the major repair in "Repairing Hull Damage the Whaler Way." Thanks for any and all input.
keltonkrew	posted 02-28-2005 07:00 PM ET (US) I used acetone in my re-do....that's what I was told to use by LBI Fiberglass....although a lot say don't use it...I went with the manufacturer's instructions.
Taylor	posted 02-28-2005 07:42 PM ET (US) Acetone from Fiberlay is eight bucks a quart, so the difference is not all that much. Yeah, I'm cheap - but when it comes to materials for a job like this, I don't scrimp. The cost savings is in doing the labor yourself. If the directions had said 'styrene' that's what we would have used. When I exchanged email with Spectrum Customer Support last year they said that gelcoat formulations had changed since I did my repair and thus their instructions had changed. There is some discussion of this in the follow up thread to the repair article: http://continuouswave.com/ubb/Forum3/HTML/003090.html
Tonym	posted 02-28-2005 09:09 PM ET (US) Some people also recomend a good laquer thinner to cut gel coat. Tonym
bdreaper123	posted 02-28-2005 10:01 PM ET (US) I used Acetone to thin my gel coat. That was what my instructions said to do. I would do what ever the manufacturer recommends.
Martman	posted 03-01-2005 08:12 AM ET (US) Wanchese, How much do you need? I purchased a gallon when spraying one of my 13' last fall. I still have at least 2/3 left. You are welcome to have some. Just email or post here. Marty
Wanchese	posted 03-01-2005 11:50 AM ET (US) Hey Marty, Thanks for the offer. I figure I need about 4 ounces or less. Hey, didn't I look at one of your boats about this time last year in Wilmington? I bought an old Nauset. I don't have your e-mail. I'll leave mine here. Drop me a line and we'll get together. Thanks, John stevensj@uncw.edu
John O	posted 03-01-2005 09:50 PM ET (US) Hello Martman, I will be in Wilmington in a couple of weeks for a little R&R and could use a small amount of gel coat myself. I would be happy to pay you for it.
Martman	posted 03-02-2005 08:14 AM ET (US) John O, I have some white (generic) gel coat and a little 1950-1972? color off white spectrum gel coat. Drop me an email on your schedule. Marty
John O	posted 03-03-2005 07:11 PM ET (US) OH, I was looking for Desert Tan. thanks anyway. I will be in Wilmington 3/17-3/20
SMLWhaler	posted 03-11-2005 02:30 AM ET (US) I used Spectrum product on the inside and outside of my 13 with excellent results. I followed their recommendations and purchased 1 quart of Slo Patch for every quart of gel coat. Worked like a charm. Kicked the way it was suppose to, ended up with a nice job. I would use what the manufacturer dictates. If it costs a little more, so what. You won't have to contemplate a redo because you took the cheap route. If I remember correctly I used 3 quarts of gel inside and 3 quarts outside. As previously stated you need 1 quart of Slo patch for every quart of gel. Its expensive no doubt. Finished product will be an accurate color match and very durable.
gtcway	posted 03-11-2005 05:56 PM ET (US) SMLWhaler, was that 3 quarts total on the inside or 6 when mixed with the slowpatch? I'm thinking about doing my 15' whaler this summer.
SSMarine	posted 03-11-2005 09:57 PM ET (US) Thinning gel-coat with acetone is not a good practice, overthining will cause problems with curing, also my experience has been that acetone changes base gel-coat colors. My best results have been with Dura-tec High gloss additive, 50/50 with gel-coat, thinned if neccessary with M.E.K. Solvent and catylized 2% (14 drops per oz.) M.E.K. hardener. The Dura-tec does not require an addition of a surfacing agent (wax) or application of P.V.A. to get a hard, tack free surface. Dura-tec also makes your gel-coat go alot farther as you mix it 50/50. Be advised that Dura-tec, like gel-coat and other surfacing agents have a fairly short shelf life. It seems most gel-coat applicators have a "recipe" that works best for them, for me this works best!!
SSMarine	posted 03-12-2005 08:43 AM ET (US) P.S. one important note on thinners, (any thinners) never thin gel-coat more than 20%. Color change and non-hardening almost certain. Personally don't find it necessary to thin more than 10% to shoot gel-coat with airbrush or HVLP gun. Improper hardening is usually related to too much thinner, incorrect hardener ratio, too low of temperature, or using a laminating gel-coat without wax or a surfaceing agent,or not covering with PVA. Hope this helps!!