Which edco grinder blocks

[GarageEnvy]

Picking up an Edco 2 ec dual head grinder to do my floor over the weekend and I've got some options.
1) Rental yard 1 is $190 with diamond (dyma-sert) blocks or grinding stone
2) Rental yard 2 is $100 with whatever blocks are on it and an additional $120 if I want the dyma-serts.

I'm doing 1800 sf so this isn't going to be quick and I don't mind paying more if it will save a few hours. Do I need the dyma-serts? Which block gives the best surface for epoxy-prep.

The concrete is new, no stains, hand troweled and power troweled smooth.

 

[SpaceEnvy]

This will probably not be the pointed reply you want.

Which diamonds always depends on the match to the concrete. The harder the concrete is, the softer bond on the diamond heads should be, and the opposite is true too. A mistake some rental yards make is assuming a one size fits all approach to diamonds for diamond grinders. If you end up with the wrong heads two things happen: You go through the head faster and the prep is less effective. I would ask the yard if they have had any success or challenges with these types of issues.

 

[nip_tuck123]

I tried the medium coarse stones and found them to work very slow on my floor. Went back and paid the extra $120 and got the dyma-serts and they worked much faster. I did 660sq ft and it took me and my son about 14 hours. Hopefully yours will go a bit faster. Good luck. It wasn't hard, but very time-consuming and frustrating at times.

 

[noslo04]

Why grind new concrete?

 

[dlewis]

Both prices are comparable,grinder $90-$100. dyma-serts $100.-$120. stones are roughly $5.Ea. is the going rate.Heres the number for Edco 800-638-3326 give them a call,tell them what you got,they will be glad to help you out.

 

[Hammerdown]

I'd go with the Dyma-Serts. They do the job quicker and more efficiently, IMHO. Edco claims they grind 5 times faster than the stones, and I'd agree they are faster and seem to take just enough of the surface to smooth it out w/o leaving swirl marks. Add weight to the top of the machine if needed to get tthem to "bite" in more. Call Edco (1800-638-3326) or www.edcoinc.com

 

[GarageEnvy]

Alright, I called Edco and they recommended the dyma-serts. They claimed it would go 250 sf per hour. I have now spent 3 hours on 110 sf and it's nowhere near. There was one glitch though. When I went to the rental place they said they only had 5 of the 6 dyma-serts so they filled the remaining hole with a grinding block. After 16 very very slow passes over the area it was still nowhere near ready. I suspected the grinding block was sitting high enough that the dyma-serts were not hitting or only lightly touching. I took the one block out and ran with just the 5 dyma-serts. I really can't say that I notice any difference. I thought about adding weight as well and will try that now. Geez, this is going to take forever at this rate. Incidentally I am running this dry. The machine has a provision for water but I'm trying to avoid using water unless I have to. I wouldn't think this would matter as the blocks aren't getting hot. I figured it was just for dust control.

 

[munkey]

I wouldn't think this would matter as the blocks aren't getting hot

I seem to remember mine getting quite hot... but the one I rented came with a LOT of weight bolted to the top part above the grinding mechanism. The machine was so heavy that I had no chance to lift it by myself, absolutely none. You definitely need weight to force the dyma-serts down into the concrete, otherwise you're probably just skimming the surface. Even with the weights it would still sometimes kinda "bounce" up from all the power when I hit an uneven spot.

 

[dlewis]

Did you flip the wheels backwards out of transport position so both discs are flat on the floor,have seen alot of people use it in the transport position.

 

[GarageEnvy]

Yep, actually saw that on the side and thought oh maybe that was it but they were in the back position when I picked them up. The only consolation at this point is that my wife has taken pity on me and taken over for a few moments. I tried adding weight (one full kit of Epoxy-Coat) on top of the machine but it made no difference. Talked to the rental company and they recommended sand to help expose the diamonds on the dyma-sert. Despite by skepticism I tried it and it was worthless. There's only about an 1/8th of an inch left on the dyma-serts and I'm wondering if maybe that last bit isn't as effective. Trying to track down a secondary source of dyma-serts for rent.

The irony is that I used this rental company because last week I went to pick the one up at another rental place who swore they had the diamond inserts only to drive 25 minutes to find that there's were totally worn out.

 

[munkey]

I tried adding weight (one full kit of Epoxy-Coat) on top of the machine but it made no difference

I swear the machine I used had over a hundred pounds of raw weights (iron or something?) bolted onto it. I don't see how a kit of Epoxy-Coat is going to make a difference unless I am vastly underestimating its mass. You need a -lot- of weight to smash that sucker down onto the ground.

Of course, if your inserts are worn out that's certainly a problem worth looking at first.

 

[nip_tuck123]

My dyma-serts were anywhere from 1/4" to 1/8" and amazingly they only had 5, not 6. Told me to use a stone in place of the 6th dyma-sert, tried that but it wasn't working so I used the 5 dyma-serts with no stone, with my 150lb son standing on the machine and that was the best I could get it to work. Did less than half of the 660sq ft the first 8 hours, but after realizing I needed ballast, having my son stand on the machine, did the other half the second day in about 6 hours. Good luck.

 

[GarageEnvy]

OK guys, problem solved. Added weight to the tune of almost 150 pounds. No real improvement. Then droplets of grease started appearing in the dust. Excess grease from motor shaft bearing has heated up enough to break free. Solve that. Then the ridiculous (in my opinion) wood wedge anchoring system for the blocks fail and the dyma-serts start falling out. Call rental company tell them it's worthless. They agree and give full refund and recommend Constar. I rented a propane powered (Honda motor) dual head grinder from Constar which makes the Edco look like pure Fisher-Price. Easily a 500 pound machine compared to the 220 (according to the sticker) pound Edco. Far better diamond which aren't anchored by wood wedges. Eighty pound steel block for ballast. Did 110 sf plus a re-do over the first 110 sf in about 30 minutes. I think I can get the whole 1800 sf in a long day.

I know others have had good luck with the Edco but I think the machine is pretty "Mickey Mouse" and clearly inferior to the Constar machine.

 

[munkey]

Glad to hear it worked out! I agree, the wood wedge system is ridiculous. They claim it is so that if you hit a high spot it gives a point of failure that isn't YOU. In other words, instead of the machine flying out of control and spinning around and hitting you, the wedges fail and the inserts come loose. But it seems like they should have come up with something better.

 

[GarageEnvy]

For the sake of others who may experience this problem here's the type of grinder I'm using. Still can't say for certain whether the Edco problems were the cutting head, the machine design or just my particular machine but for me this machine gave better results.

http://www.ohiopowertool.com/p-1979-diamond-13-hp-honda-double-head-floor-grinder-cc213h.aspx

 

[Jaguar Fan]

For the sake of others who may experience this problem here's the type of grinder I'm using. Still can't say for certain whether the Edco problems were the cutting head, the machine design or just my particular machine but for me this machine gave better results.

http://www.ohiopowertool.com/p-1979-diamond-13-hp-honda-double-head-floor-grinder-cc213h.aspx

Thanks for posting. Glad it worked out. I've bookmarked this for the future.

 

[GarageEnvy]

Well a full 27 hours of grinding later I'd have to say that although the new machine is far better than the old one I'm still a bit disappointed with the results. I knew this would be slow going but I wasn't prepared for how slow. You can see from these photos that it's still real spotty with low spots. For the amount of dust it creates you'd sure think that it was taking more off.