Resin issues in sun light

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Resin issues in sun light

Author	Message
BMac	B BMac posted 4 Years Ago HOT Topic Details
B Group: Forum Members Posts: 14, Visits: 50	I recently used your carbon fibre skinning kit on a car product. I measured the resin to exactly 3:1 ratio in good conditions at the start of summer. The resin cured fine and I got it to a great finish. However 4 days after installing the product in the outside of the car the direct sunlight has caused the resin to form ripples in line with the carbon fibre. They are all equal straight lines. The resin has developed a greyish tone to it. Can you explain why this has happened. I am working on two other car parts and I'm afraid to out them on the car in case the same thing happens. Thanks B
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Lester Populaire	L Lester Populaire posted 4 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x BMac - 7/6/2020 9:43:59 PM I recently used your carbon fibre skinning kit on a car product. I measured the resin to exactly 3:1 ratio in good conditions at the start of summer. The resin cured fine and I got it to a great finish. However 4 days after installing the product in the outside of the car the direct sunlight has caused the resin to form ripples in line with the carbon fibre. They are all equal straight lines. The resin has developed a greyish tone to it. Can you explain why this has happened. I am working on two other car parts and I'm afraid to out them on the car in case the same thing happens. Thanks B You really need to post cure car parts before exposing them to heat. And to have a lasting part you need to paint them too. With a hand laminating resin where the glass transition temperature is not going to be higher than 80°C typically I'm not even sure you can get a lasting finish at all. Typically i try to stay 20°C under the Tg during use. The clear coat is needed for uv resistance. Hope this helps Cheers!
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BMac	B BMac posted 4 Years Ago HOT Post Details
B Group: Forum Members Posts: 14, Visits: 50	+x Lester Populaire - 7/7/2020 7:20:56 AM +x BMac - 7/6/2020 9:43:59 PM I recently used your carbon fibre skinning kit on a car product. I measured the resin to exactly 3:1 ratio in good conditions at the start of summer. The resin cured fine and I got it to a great finish. However 4 days after installing the product in the outside of the car the direct sunlight has caused the resin to form ripples in line with the carbon fibre. They are all equal straight lines. The resin has developed a greyish tone to it. Can you explain why this has happened. I am working on two other car parts and I'm afraid to out them on the car in case the same thing happens. Thanks B You really need to post cure car parts before exposing them to heat. And to have a lasting part you need to paint them too. With a hand laminating resin where the glass transition temperature is not going to be higher than 80°C typically I'm not even sure you can get a lasting finish at all. Typically i try to stay 20°C under the Tg during use. The clear coat is needed for uv resistance. Hope this helps Cheers! Thanks for the reply. I let the part post cure for 1 week before sanding and polishing. Then 4 days before putting it on a car. I am using the XCR Resin which should surely be able to handle summer sun in the UK. Max temp here in NI was 24C I am hesitant to spray paint the product because using acrylic lacquer is a waste of time and 10x worse at rippling in the sun than the current finish. I know cause i tried it before and when i used a hair dryer on the paint it was horrible. So that leaves 2K hard lacquer. Is 2k Lacquer compatible with this resin though? Again i have used 2K on parts before whereby if the undercoat is not compatible you end up with a spider web effect which is very messy.
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BMac	B BMac posted 4 Years Ago HOT Post Details
B Group: Forum Members Posts: 14, Visits: 50	I had a read of the XCR pdf. I didn't realise that there was such a long ambiaent and post cure time for surface heat. Would this just apply to direct sun light on the part. ie if i had the part installed but a car cover on would this prevent it enough so i dont have to wait two months before installing on car?
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x BMac - 7/7/2020 12:11:06 PM I had a read of the XCR pdf. I didn't realise that there was such a long ambiaent and post cure time for surface heat. Would this just apply to direct sun light on the part. ie if i had the part installed but a car cover on would this prevent it enough so i dont have to wait two months before installing on car? No, it is the heat. If the car cover doesn't reflect enough heat to prevent the part going above it's glass transition temperature then you will still experience print through.
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MarkMK	MarkMK posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	Just to add to the above...skinned parts are quite rich in resin content, so they are quite prone to resin shrinkage and the print-through effect mentioned by Hanaldo, with little exposure to the elements Overall, they aren't the most resilient to the effects of sun exposure. If you post-cure them prior to performing the final flatting and polishing work, the shrinkage can be accelerated, which should bring on the rippled print-through surface you've experienced. You can then look to flat this back and finish the parts when the resin is in more hardened state. Coating with an auto-quality clear coat will help maintain their appearance beyond this, as already mentioned
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BMac	B BMac posted 4 Years Ago HOT Post Details
B Group: Forum Members Posts: 14, Visits: 50	Thanks folks for the advice. I guess I'll have to wait two months to fully cure before applying. Pity as they do look superb in the sunlight.
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Lester Populaire	L Lester Populaire posted 4 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x BMac - 7/8/2020 8:04:27 AM Thanks folks for the advice. I guess I'll have to wait two months to fully cure before applying. Pity as they do look superb in the sunlight. No i think you are misunderstanding post curing. You need to bake the part at elevated temperatures according to the tds. Even with 2 month of curing at ambient the Tg won't rise significantly. 2k paint is the only way to go. The 2k spray cans that one can buy are surprisingly good if you don't have access to a paint booth. Post curing is way more important for the part tho
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