Sanding, time per square foot

[mox90291]

Just wondering if anyone has kept track of sanding a Large are. I've been asked to restore a red Mahogany fence about 120 lineal of 8 foot . The fence has been coated with 1 maybe 2 light coat of polyurethane and is badly peeling. Thinking of using my ro150 for the whole job. starting with 80  then 150 finishing with 220. so, 3 passes, I feel I'm looking at 3 days at half a minute per foot.
any thoughts?

 

[Wooden Skye]

I agree that removing and using a drum sander would be best.  However maybe power washing and sanding would be a back up option.

 

[waho6o9]

Remove the boards and install new ones.

 

[tjbnwi]

Call a soda blaster.

Tom

 

[RJNeal]

At 8' tall you will most likely need a ladder or step stool which takes time.  Depending on the old finish removal and sanding disc clogging. I would guesstimate 10 mins or so a board.
Good luck.

 

[antss]

Sorry I don't have any historical figures to give you for this type of operation, but I estimate labor on carpentry jobs all the time.

No way you are going to average a foot every thirty seconds for that operation.  If you were just lightly sanding material in good condition to key it for new finish then, yes.  But that's not what you said you have.

That job is by the hour only , no flat rates or bids.  And no discounts.  An 8' tall fence out of Mahogany is pretty rare and very expensive to begin with.

 

[semenza]

Just wondering if anyone has kept track of sanding a Large are. I've been asked to restore a red Mahogany fence about 120 lineal of 8 foot . The fence has been coated with 1 maybe 2 light coat of polyurethane and is badly peeling. Thinking of using my ro150 for the whole job. starting with 80  then 150 finishing with 220. so, 3 passes, I feel I'm looking at 3 days at half a minute per foot.
any thoughts?

Hi,

  Welcome to the forum!  [smile]

      That is definitely a job that will take longer than you think. 

      Do you need to do both sides?  Edges of boards? Sand close to the ground? 

      Some pics of the type of fence would be good to help see what the job really is going to be like.

     
Seth

 

[lwoirhaye]

I think the only sensible way forward is to remove the boards and run them through a sanding machine.  It will both save the client a lot of money and save you the  discomfort of holding onto a sander on a ladder for hours on end.

 

[Holmz]

I think the only sensible way forward is to remove the boards and run them through a sanding machine.  It will both save the client a lot of money and save you the  discomfort of holding onto a sander on a ladder for hours on end.

I was thinking the only sensible way is not forwards, but rather to chuck it into reverse and get out of there.

Even Huckleberry Finn would not likely tackle that.

 

[BJM9818]

In July I sander down a rain screen that wrapped around a good deal of a popular bar here in town. Wood may have been Morado. 9-12' high 6" wide boards installed horizontal. There was a lot of grey weathering and some old finish to sand off.  Total of around 3000ft2.

Three guys in three days sanded 95% of the wood. I hit it first with a Ras115 with either 40-60grit then went back with the Rotex using 60-80 grit depending on how bad the wood was. 

By the fourth day job was completed abd had a new coat of stain on it.  The wood had V groves so it had to be hit with the ro90 delta pad which ate up a ton of time.

 

[antss]

So, 72 man hours for sanding. 

Mox, your estimate is almost twice as ambitious as BJM's

 

[BJM9818]

So, 72 man hours for sanding. 

Mox, your estimate is almost twice as ambitious as BJM's

He didn't say if he was doing both sides?  It also was 95 degrees out which caused the RAS's to keep kicking on and off. I would say one guy spent 1 1/2 days just sanding the V grooves which again were a total PITA. 

 

[Pnw painter]

Like tjbnwi said, I'd get an estimate to have it media blasted.

Another alternative is to strip it, but I'm not sure what product would work best. You could contact PressureTek to see what they'd recommend.

Personally, there is no way I'd attempt to sand a project like that unless it was T&M. Another alternative is to include allowance of 4-6k (or whatever number you choose) for prep worn in your quote.

Also, there is no reason to sand up to 220. With many exterior stains/clears you're not supposed to go beyond 150.

Sent from my iPhone using Tapatalk

 

[antss]

BJM - did you consider the LS130 to sand those v-grooves ?  That would have been better than the ro90 I'd think.

 

[semenza]

[member=51340]mox90291[/member]  It would be good to know how you are progressing with this job.

Seth

 

[BJM9818]

BJM - did you consider the LS130 to sand those v-grooves ?  That would have been better than the ro90 I'd think.

The LS pad was just to big to get into the entire V notch. It worked with a fresh piece of paper but quickly rounded off and left the inside unsanded.