Floor grinding crossroads

[thomapa1]

Getting ready to lay down Armorclad / Armorpoxy 100% solids 2 part epoxy soon. After looking for floor grinder equipment - I am getting frustrated at the escalating costs. However I want to do it right.
My floor is 500 sq ft and currently has an @12 year old paint job on it - it is not thick, not sure what kind of product was previously used...likely a cheapo product. Otherwise, the floor is in great shape - no high/low spots - just a few shallow divots that I can prep and patch prior to new epoxy coating. Anyway, to prep the floor, I'd prefer to remove the old paint job and grind enough to prep for the new epoxy.

During my research, I came to the conclusion that the existing topcoat of paint should be stripped (using the grinder mfg appropriate stripping attachment) prior to grinding with stones or diamond attachment. Bottom line, when drops of water are thrown on the floor, they should be absorbed - not laying on top. If laying on top - you need to grind more.

Option #1 - get it done in a day
Rent a machine (Edco or Stow - only electric are available near me) $100. Rent Strip insert ($125), Rent Diamond insert ($125). The Stow rental is cheaper - but does not offer the diamond or strip inserts - therefore I am taking a chance to try to do it all with stones only...not sure how fast the stones would wear out.
Would still need to get the corners, so say another $100 to rent an angle grinder for a day.
$450

Option #2 - Grind at my leisure
Buy a 7" angle grinder (say $150 - however Harbor Freight has a $45 unit) - I cannot find a variable speed unit with a vacuum attachment - not sure if the 8,000 rpm or whatever would do more damage.
Diamond cup wheel ($95) and some kind of dust shroud attachment (that seem to get poor reviews for effectiveness) $30. Could likely get it done over 3-5 days.
@$200-$300

your thoughts?

 

[chickenhauler]

Hitachi grinder from Lowes - $109
7" Dewalt cup wheel from Lowes - $80?
Dust Buddie and Shop vac bags from Amazon - $115

 

[thomapa1]

Thanks...I am seeing a few folks use the Bosch 1773AK 5" setup with dust collection / diamond wheel.
I am leaning towards doing it 'by hand'
Any problems given the RPM speed? I previously read where lower speeds were desireable - how's the final outcome? swirl marks, etc?

What other grinder recommendations?

FYI - I found this other product which should help with collecting the dust...
http://www.oneida-air.com/inventory.asp?CatId={6EE79B16-EB63-43E7-8F30-1E06240A24A4}

 

[flyng_fool]

Have you looked into renting a shotblaster? It's supposed remove the epoxy and prep the floor in only two passes.

This is the best video:

 

[thomapa1]

I believe shot blasters would cost me in the $300-$600 range -trying to minimize cost on this portion of the job

 

[Gearhead559]

i am renting one of these..

http://www.volvorentsconstructionequipment.com/walk-behind-concrete-planer-wcarbide-teeth

its about $160 with 3 discs for a day

 

[LegacyIndustrial]

Have you considered a buffer rental($100-200) and a Diamabrush Head ($300-400)? Better than spending the day on your knees.

Link: http://legacyindustrial.net/cart/mastic-tool-p-296.html

 

[thomapa1]

No - I have not thought about buffer / diamabrush because $400-$600 is more money than I wish to spend.

Let me rephrase my question...
What is an economical way to prep my garage floor for epoxy? Given that it has a poor and thin covering on it now. I do not mind doing work myself to save money.

So far - it looks like the Bosch 5" grinder 1773AK or a standard 7" angle grinder with diamond cup wheel and some kind of dust / vacuum attachment is the best choice.

 

[Garage Flooring]

See thread http://www.garagejournal.com/forum/showthread.php?t=134669

I know it is not the information you want, but the cost of doing it right the first time is far less than going back and doing it again.

 

[thomapa1]

Thanks for the advice..think I'll rent the Edco with the strip attachment and diamond attachment, then buy a small diamond grinder for corners and be done with it in a day for @$450 vs trying to knock it out with a hand grinder.

 

[dcs Inc]

Aren't the strips certs just for removing glues and such? The diamonds should be all you need. Guess i should drop by my local rental company and take a look. Your best bet would be the edco 10" single head grinder with a cup grinder head attachment. The double heads are a PIA and really don't do any better besides those wedges **** to keep in place.

As far as dust, wet grind it. Yes it's messy but no dust and the slurry isn't hard to clean up. Should be able to get in and out for under 2 to 300.

Also, look for the 7" stand up grinders. A lot of rental companies rent these. these will get close enough into the corners and ae pretty fast. Usually have to buy the cup wheel. I have a 12 segment turbos that work real well for $65.00. Again, wet grind and play in the mud to save on the vac rental. gene

www.elitecreteindiana.com
www.indycrete.com
[email protected]

 

[ISLANDEQUIPMENT]

Talk to your rental guy he might give you 1/2 day rate we have stones from 100 grit to 8 grit for the edco throw water down & can use sand too

 

[Edger]

If you can get hold of the buffer and diamabrush head I reckon it will be cheaper and better than doing it any other way. Then you should buy a cheap 5" grinder, 5" plastic shroud, 5" cupwheel and shop vac bags for the edges.

Second suggestion is to use the 9" Hitachi grinder shown above with clear shroud. If your concrete is too hard you may have to invest in a "soft bond" diamond cupwheel. The photo accompanying the grinder is a true indication of how it will turn out.

 

[thomapa1]

I'll look at the Edco single head turbo unit - thanks.
Overall, I am confused as to whether I can only use a diamond head to remove the existing old coating (poor quality - likely Home Depot garage floor paint) - or if I need to do it in stages...stage 1 = strip cert attachment to remove the old coating, stage 2 = diamond head attachment (or stones) to open the pores as prep for epoxy.

I'd hate to start the job, then find out that i don't have the correct attachment

 

[LegacyIndustrial]

I'll look at the Edco single head turbo unit - thanks.
Overall, I am confused as to whether I can only use a diamond head to remove the existing old coating (poor quality - likely Home Depot garage floor paint) - or if I need to do it in stages...stage 1 = strip cert attachment to remove the old coating, stage 2 = diamond head attachment (or stones) to open the pores as prep for epoxy.

I'd hate to start the job, then find out that i don't have the correct attachment

I can't speak to the Edco. However, the diamabrush mastic remover tool will strip off that paint and leave it ready for coating in one step.

Also...
If you have meat left on the tool when done, another GJ person will likely buy it from you or you could sell it on ebay. The brushes are replaceable.

 

[munkey]

So far - it looks like the Bosch 5" grinder 1773AK or a standard 7" angle grinder with diamond cup wheel and some kind of dust / vacuum attachment is the best choice.

For what it's worth, my garage was about the same size as yours and I rented the full size Edco machine. But, it was a bit of a pain and didn't do the job completely to my satisfaction -- not only can it not do the edges, but it also couldn't "push" hard enough to get many of the harder and/or lower spots. (This is despite the fact that it had many very very heavy weights installed on it.) So, I ended up renting the Bosch unit you speak of and it worked FABULOUSLY. It's a great tool.

With the rental fees and supplies, I could have been well on my way to buying the 1773AK. I regret not having bought it to begin with every time I think about the garage epoxy project.