Flowcoat sagging

[bob26]

Having made a gas bottle box with ply covered in grp I tried to cover in flowcoat.

The bottom was fine - though it took a while to go off - but the vertical sides sagged horribly leaving ridges and cracks like the icefalls at Everest base camp.

Is it not possible to apply flowcoat on vertical surfaces or did I :

a. use too little hardener? or
b. work in too low a temperature (it was probably about 6-8 degrees C in my garage last night)? or
c. Not rough up surface enough?

Should I have left the grp laminate to cure longer - or applied flowcoat sooner?

As I understand flowcoat is gelcoat mixed with wax which creates a surface coat, presumably I have to grind all this mess off completely before I attempt to redo?



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[stretch33]

Bob I've just done my engine compartment and various other bits with flow coat, all went off well except for one item - the battery box. All the other bits were sanded with 80 grit and then wiped over with acetone prior to applying the coat. Coz l was in a hurry l did not wipe the Battrey box over with acetone and l ended up with a goopy mess like you. You'll have to clean it all off (sh***y job) then sand and wipe with acetone and do it all again. I also added a little extra catalyst to speed things up a bit on the vertical surfaces. Mines fine now after a considerable amount of swearing to myself. Make sure no condensation on the bits your going to do. Good Luck

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[Avocet]

I think the temperature was too low - it does have quite a pronounced effect on the time it takes the resin to "gel". With ordinary laminates, the resin gives off heat as it cures but the peak heat output time is after it has gone "jelly-like". If you have several layers together, the heat build up in the middle can be quite severe and damage the item. With a flow coat, it is such a thin layer that it can't really retain any heat and resins rely to a certain extend on their own heat to help curing. Try using the maximum amount of catalyst allowed by the manufacturer in your next "brew". I tend to increase it a few percent beyond that for good measure but I'm not sure that's good advice - I'm just impatient! Also, were you using a lot of pigment in the flow coat? I've heard that pigments can inhibit curing. If the item is small enough to do in your garage, can you turn it so that each side is horizontal when you coat it?

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[PuffTheMagicDragon]

It is also possible that the styrene fumes could not drain away, being in a box. They are heavier than air and, if not removed, will tend to prevent the resin from setting because they are excluding the air (they are not like gel coat). I find it useful to arrange for a flow of air, e.g. by setting up a small electric fan to provide for a good rate of air changes. In the case of boxes, if they are not built-in, you can simply lay them on one side. It helps.
Fair Winds!

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[oldsaltoz]

G'day Bob,

Not a good practice to apply resin in cold conditions and even worse to apply if the temperature is dropping as you may reach dew point.

If its a catalyst/wax resin in styrene, (Most are). Then do the job on the weekend about 10 am. or at night with a fan heater.

add 2% catalyst, mix well, apply, add fan and some heat. It should go off in less than 30 minutes.

I hope this helps....



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[snowleopard]

you gan increase the viscosity of resin by adding 'thixotropic gel'. this is a really sticky resin containing a high proportion of thickening agent that you mix in before applying. if you add enough the resin will virtually stand up on its own

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