Go Back   Forno Bravo Forum: The Wood-Fired Oven Community > Pizza Oven Design and Installation > Tools, Tips and Techniques

Like Tree3Likes

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-04-2014, 02:25 PM
Apprentice
 
Join Date: May 2013
Location: Ireland
Posts: 169
Default Is a variable speed grinder essential?

Hi guys, I'm having a hard time finding a variable speed grinder for reasonable money. I'm wondering, is it possible to polish concrete with a normal grinder? What's the downside of this and would it just require some additional care?

Thanks

R
Reply With Quote
  #2  
Old 01-04-2014, 04:03 PM
Gulf's Avatar
Il Pizzaiolo
 
Join Date: Sep 2011
Location: Mississippi
Posts: 1,660
Default Re: Is a variable speed grinder essential?

Rich,
I've seen where some have added "variable speed rheostat controls" to their's.
My grinder is not variable speed, but it worked fine for me on my small project.

EDIT: I might better add that I have only used the upsided down method for pouring counters. Since this method already has, most of what is wanted to be seen at the surface, it is mostly polishing with the more finer grits. But, in my case at least, the cheap grinder worked just fine.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by Gulf; 01-04-2014 at 05:51 PM.
Reply With Quote
  #3  
Old 01-04-2014, 06:48 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,379
Default Re: Is a variable speed grinder essential?

you can get a router speed controller from Amazon for $18. I used this and it worked fine to control the speed of an electric motor. No reason to step up to a VS grinder. Actually, you are better off with cheapy since you're going to expose it to a lot of water. The speed controller also has a GFCI fuse in it, which is helpful when you're standing in a pool of water...

Amazon.com: SE Electronic Stepless Speed Controller: Health & Personal Care
Gulf likes this.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #4  
Old 01-05-2014, 12:20 AM
Apprentice
 
Join Date: May 2013
Location: Ireland
Posts: 169
Default Re: Is a variable speed grinder essential?

Thanks guys!thsts a much better solution for me. How precise does speed control need to be for concrete polishing? Do you just turn it down and judge by the sound if it if it's at 50% of max? Or do you need to be within specific speed ranges depending on pad grit?

Thanks

R
Reply With Quote
  #5  
Old 01-05-2014, 05:39 AM
stonecutter's Avatar
Il Pizzaiolo
 
Join Date: Jun 2007
Location: South Carolina,USA
Posts: 1,891
Default Re: Is a variable speed grinder essential?

You could get diamond hand pads instead of cobbling something together. I've used non- insulated tools for polishing stone and concrete, it works well enough, but I wont recommend it. It's dangerous, and an unnecessary risk...especially since this is a personal project where you don't have a deadline or a client to please, consider a safer route.

Diamond hand pads come in grits from 50- 3000, and they work great. I do have a vs wet polisher, but I use the pads just as much, if not more, because they can finish areas that the polisher can't.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Current WFO build -
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


When we build, let us think that we build for ever.
John Ruskin

Last edited by stonecutter; 01-06-2014 at 07:03 AM. Reason: sp
Reply With Quote
  #6  
Old 01-05-2014, 08:42 AM
Apprentice
 
Join Date: May 2013
Location: Ireland
Posts: 169
Default Re: Is a variable speed grinder essential?

@Stonecutter, I didn't know it was possible to do this by hand! I'm casting in situ and intend floating some broken glass into the surface. My total surface area is about 3m^2. Is it really feasible to get a glassy sheen by hand? Is it going to take a ridiculous amount of time? Some areas will be difficult to access with the grinder. I'd prefer to do this be hand if it's a realistic approach? If doing it by hand what grits should I be buying ?
Reply With Quote
  #7  
Old 01-05-2014, 09:39 AM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,379
Default Re: Is a variable speed grinder essential?

My experience was that you run the speed up to where it feels like it is working, it's pretty easy to gauge.

FWIW, I didn't feel unsafe using the grinder. Rubber gloves +rubber boots + GFCI. Only popped the fuse once and I knew why.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #8  
Old 01-05-2014, 10:29 AM
stonecutter's Avatar
Il Pizzaiolo
 
Join Date: Jun 2007
Location: South Carolina,USA
Posts: 1,891
Default Re: Is a variable speed grinder essential?

Quote:
Originally Posted by RichC View Post
@Stonecutter, I didn't know it was possible to do this by hand! I'm casting in situ and intend floating some broken glass into the surface. My total surface area is about 3m^2. Is it really feasible to get a glassy sheen by hand? Is it going to take a ridiculous amount of time? Some areas will be difficult to access with the grinder. I'd prefer to do this be hand if it's a realistic approach? If doing it by hand what grits should I be buying ?
If you are seeding your pour with glass or aggregate, then I would recommend power tools. But to answer your question, yes, you can get a glass like surface with hand pads.

What grits you would need depend on how your concrete is troweled off, type of aggregate used, and what you want to see as a finished surface.

You can buy a variable speed grinder and dry polishing pads ( metal bond vitrified are good) for a reasonable amount of money (google). Use respiratory protection when you dry grind. Metal bond pads are aggressive and usually only go to 200 grit. From there you can get resin bond and higher grit. Keep in mind, you want to use resin bond at lower rmp, otherwise the pads can burn.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Current WFO build -
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


When we build, let us think that we build for ever.
John Ruskin
Reply With Quote
  #9  
Old 01-05-2014, 10:46 AM
stonecutter's Avatar
Il Pizzaiolo
 
Join Date: Jun 2007
Location: South Carolina,USA
Posts: 1,891
Default Re: Is a variable speed grinder essential?

Quote:
Originally Posted by deejayoh View Post
My experience was that you run the speed up to where it feels like it is working, it's pretty easy to gauge.

FWIW, I didn't feel unsafe using the grinder. Rubber gloves +rubber boots + GFCI. Only popped the fuse once and I knew why.
I'm not trying to be a safety cop with grinder use, that would make me a hypocrite in this dept.

None of my grinders have guards or handles. I don't feel unsafe, and I have been doing it for years with no problem. That doesn't make it a safe practice...especially when people that aren't use to working with them that way are trying a technique for the first time.

I stand behind my previous post. It may have worked fine and dandy for you, but I won't recommend doing stuff the way I do it, if I had to modify technique and tools outside of standard safety practice...even if the results achieved are spectacular.

Let the readers/builders use discernment.....
deejayoh likes this.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Current WFO build -
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


When we build, let us think that we build for ever.
John Ruskin
Reply With Quote
  #10  
Old 01-05-2014, 10:52 AM
Apprentice
 
Join Date: May 2013
Location: Ireland
Posts: 169
Default Re: Is a variable speed grinder essential?

Thx guys, back to grinder with speed control then never polished concrete but well used to power tools! Do you need to start this process shortly after pour or is it best to wait longer ? Or can I leave it until I find the time to get to it?
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
hobart mixing speed lane Pizza 5 10-17-2013 09:46 AM
Forno Bravo at 10 Speed Press james Introductions 2 07-28-2006 06:27 PM


All times are GMT -7. The time now is 07:17 AM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC