Hpu 747

[Harley63]

New guy here. I’m about to do my 500sq foot garage next week in epoxy and do a high broadcast flake l. The coating store told me to buy 2 HPU 747 kits l. Put one coat down wait and put another coat down. I’m not looking for a glass finish so I don’t bust my *** but want it to be shinny. My question is. Can I put both kits down at one time? Also it says to de shine before the 2nd coat so was trying to avoid sanding the floor for the 2nd time. ( they failed to tell me I needed to do that before ordering) any help would be appreciated and pictures maybe of 1 coat vs 2 coats. Or an easy way to de-shine the 1st coat.

 

[Shea]

What is your definition of high broadcast? It that a heavy broadcast, but you still see the epoxy or do you mean a full broadcast with no epoxy showing?

The coverage rate for HPU 747 is 400-500 square feet. The 500 square feet would be for smooth surfaces. If you are going for a heavy flake coverage, the first coat may or may not make it all the way. The second coat will go slightly farther. I would recommend using a 1/4" roller.

If you are going with a full flake broadcast, then you will need both kits for just one coat. This is because the flakes will reduce the coverage rate quite a bit.

Polyurethane needs to be applied thin. Do not apply it thick if that is what you are thinking. Also, do not mix both kits together at the same time. Do one at a time.

 

[Harley63]

Yes full with no epoxy showing. So I should do what they said and use one kit then wait and recoat with a 2nd kit?

 

[Shea]

No. 1 kit will not go the entire 500 square feet of coverage with a full flake floor. The most you would get with no flakes would be 500 square feet. All the nooks and crannies of a full flake floor are going to **** up the polyurethane. The first kit may go 350- 400 square feet at best. You will need to continue with the second kit to cover the rest of the floor for a total of 1 full coat with some of the second kit left over.

I would recommend using three 1.5 gallon kits for a total of 2 coats. One coat of polyurethane on full flake floor is not enough. Apply the first kit. Mix only half of the second kit to finish off where the first kit ended. This is your first coat. After it cures 8-12 hours, mix the full third kit and then finish off my mixing the other half of the second kit for where the third kit stops. That would be your second full coat.

 

[Harley63]

Alright I’ll try to call them today and hopefully I can get another kit in a week so I can get it done next weekend

 

[Harley63]

Just curious. Why wouldn’t I just mix the 2 1/2 gallons together and mix them at the same time so they both dried at the same time?

 

[Shea]

2-part coatings are exothermic. In other words, they release heat when mixed. Too large a volume creates too much heat and will severely reduce pot life. That is why you don't see 2 component kits that you mix together for coatings in volumes larger than that.

If you were to apply a single-part moisture cured polyurethane you wouldn't have that issue.

 

[Harley63]

Aaahh. Makes sense


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