Replies

1. 
   Joe_Hennessey | Oct 16, 2000 02:36am | #1

   *
   Johnnie, you can either double or eliminate the human error by walking to the other end and reading the laser spot yourself. Up to you. Joe H

1. 
   Joel_Greer | Oct 16, 2000 02:39am | #2

   *Still hung up on that rod thing, huh Johnnie?

1. 
   Gabe_Martel | Oct 16, 2000 02:50am | #3

   *We always use the laser for general site work and grading. We use the level/transit for exacting work and laying out or site surveys.On the project that I'm doing now, we just put our laser away and are now depending on our levels for the slab pour. Arena ice surfaces must be within 3/16th of an inch over 20 feet. This includes the sand base as well as the concrete or the slab will crack when pulling it down.GabeGabe

1. 
   splintergroupie_ | Oct 16, 2000 04:20am | #4

   *Johnnie, i'd suspect your question is in regard to the house you are planning to GC...if so, i'd like to recomend a wallet- and user-friendly tool called a "Robolaser" available for $259 from Tool Crib. It is self-levelling, has a remote control for one-person operation, tells you if it's been jiggled out-of-level, and its very bright red dot can be easily read in direct sunlight. It doesn't have the advantages of higher-priced lasers of splitting the beam to make lines, or show verticals or 90 degree corners, but it has saved me many hours setting doors and windows, beams, stairs, and cabinets in addition to foundation work, and at a smaller price than most transits with fewer features. I bought one to set forms for my last foundation with my concrete contractor, who consequently bought one himself. We tested the lasers against one another at approx. 75' and the dots were smack on top of one another.However, if you're building an ice rink, i can be of no help whatsoever, and you'll need a pro like Two Gabes. ;-)

1. 
   Mike_Smith | Oct 16, 2000 05:24am | #5

   *generally speaking .. a builder's level / trasitand a builders laser have about the same accuraccy.if you want greater accuracy you have to lay out more money for a better transit or a better lazer..teh old standard for building acuraacy was a t-16.. and for survey accuracy a t-2... the laser instruments for survey work are comparable..one advantage of the laser, especially the self-leveling types described by SG is the lazer materializes on teh surface you're working with..you can do one-person operations..and tehy alert you if they go out of level...for residential work , i'd use the self-leveling laser...but get teh kind that has at least plum and square features ( three beams)...b but hey, whadda i no ?

2. 
   Don_Reinhard | Oct 16, 2000 05:58am | #6

   *Gabe: Your transit/optical level has to be better than mine if it is better than a laser (Light Amplification by Stimulated Emission & Recombination - just thought I'd pick a little nit there.) for level accuracy. A theodolite, perhaps, but not the average, run of the mill contractor's level or transit. 3/16 at 20 ft equates to nearly an inch at 100 ft. That's almost good enough for waste water pipe. My Robo-laser is 1/8 at 100 ft. I matched my Robo-Laser against my carpenter's level for doing the sill plate nearly 10 ft up on a Poly Steel ICF wall. He was adamant that the level was the way to go. Spent hours leveling, marking walls and mucking around w/ scaffolding that was in his line of sight. I spent ten minutes setting up the laser and insuring it was level, and He walked arouind the perimeter being the target for me. I managed to keep him from looking down the bore. Laser gave him better accuracy than the level, which ALWAYS worked from indirect measurements from a line 5 ft below him. If you don't beat the Devil out of the laser, it will keep its level and calibration nicely - and you can self-calibrate. We users cannot do that w/ a level. Cost me over $80 to have my CST Berger level calibrated. The grief I went through to find out it wasn't accurate was a lot more.Don Reinhard - neophyte builder, and long ago surveyor.

3. 
   Jeff_Clarke_ | Oct 16, 2000 02:24pm | #7

   *My factory-reconditioned Robilaser from Tool Crib was $209. It seems like a good tool, self-leveling within 10 degrees. Don't drop it or recalibration is needed. You also have to remember that when the window is open it's using battery power. Spare batteries on hand. Like any tool it's good for some things and not others. Great for spot elevations, foundation setup, etc.BTW -b Laser - Lightb Amplification through theb Stimulatedb Emission ofb RadiationJeff

4. 
   Gabe_Martel | Oct 16, 2000 02:56pm | #8

   *Don,When measuring surfaces we don't compound + or - our variables. What this means is that no where can there be a variable greater than 3/16 over the entire 16,000 sq. ft.The original poster was interested in what others used and why.This is what we do and this is why.Gabe

5. 
   Gabe_Martel | Oct 16, 2000 03:00pm | #9

   *DF, I would appreciate it if you didn't reference me with your drivel.Gabe

6. 
   The_Tennis_Court_Builder_...on_t | Oct 16, 2000 03:08pm | #10

   *Johnnie,The laser is a one man tool, and the transit is a two man tool. Both are as accurate, as the user has ability, to use it. Tennis courts done well are done with laser guided grading equipment. And we also shoot for less than a 1/4" over the whole tilted plane of the court. 1/8" is what we are looking for (the thickness of a nickel). The same equipment we use is the best for building ice rinks also. Gabe may be subbing his grading to someone who has access to specialised graders like we use. Spectra Physics for me...I recommend the David White 2150 for builders. The others mentioned here are toys for remodelors and DIYers.near the stream,aj

7. 
   splintergroupie_ | Oct 16, 2000 05:21pm | #11

   *People in Hell want ice water.

8. 
   Johnnie_Browne | Oct 17, 2000 02:05am | #12

   *Is it spectra physics or spectra precision. i got a brocedure from spectra precision.

9. 
   Gabe_Martel | Oct 17, 2000 02:10am | #13

   *How would you know, DF.Gabe

10. 
    The_Tennis_Court_Builder_...on_t | Oct 17, 2000 02:16am | #14

    *Johnnie,In 1997 Spectra Precision chose a new name to represent the reorganization and combination of several companies who have been part of another organization. Actually, the new name represents some of the oldest names in our business. This new combination is full of the pioneers in the modernization of measuring and control technology in the construction business. Before we changed our name we were four individual companies with a common corporate owner. Those companies: Geotronics, Spectra-Physics Laserplane, Plus 3 Software, and Quadriga all had strong reputations and brand names in the construction and civil engineering industry.We believe that gathering under a single banner has sparked the synergy to help continue our strong performance at delivering innovative solutions to our customers. Spectra Precision is now (a U.S. company) our ultimate parent Thermo Electron Corporation.There are five primary Spectra Precision locations with concentrations of our people and manufacturing capabilities. Atlanta, Georgia is home for Spectra Precision Software. Danderyd, Sweden has our Spectra Precision Surveying group. Residing in Dayton, Ohio are the Construction Instruments Area and Machine Control Area. Kaiserslautern, Germany has our Craftsman Instrument group. Also in Germany we have partnered with Karl Zeiss Company to produce Surveying Instruments in Jena, Germany. Spectra Precision is part of the group of companies owned by Thermo Instruments Systems, Inc. (THI). Thermo Instrument Systems is largely owned by Thermo Electron Corp. (TMO).History can only be an indicator of the future. Our commitment to this industry and our customers is primary in our thoughts. We will continue to grow, we will continue to serve our customers well, and we will continue to be profitable for our stockholders. We expect not only to work hard but have some personal satisfaction and fun in the process. If you are looking for a good place to work send us your resume.Spectra Precision, Inc.5475 Kellenburger RoadDayton, Ohio 45424 - 1099Phone: 937-233-8921Fax: 937-233-8543Please visit our web site at:http://www.spectraprecision.comnear the laser stream,aj

11. 
    Gabe_Martel | Oct 17, 2000 02:31am | #15

    *No AJ,I've done large indoor tennis courts and ice rinks are much different.The first layer of piping is layed about 8" below finished grade and are used for heating the ground and preventing permafrost under the slab.The next sand layer covers the warm pipes and must be spread with a track machine so as to not damage the piping.We have to screed the sand the same way as you would concrete, within the same tolerances and we use a survey team to guaranty this during the entire procedure.Next we use a layer of heavy poly, two layers of SM and a second layer of poly.Over this we install the cold pipes and re-enforcing steel, all on special chairs to make sure of the elevations.We bring in 2 pumpers for the pour, one to use and a second one as a backup. In order for a slab of about 15,000 sq. ft to not crack it must be poured continuously without breaks or cold joints. The secret to having a large slab not crack is to make it absolutely consistent in thickness and perfectly flat over a 100% compacted base. As a large slab cures, it will tend to crack where ever it defers in thickness. As you know, we install control joints by cutting into the concrete by an inch or so. This will make a weak pattern for the crack to follow, instead of randomly following the thinner patterns in the poured slab.We then do a wet cure and after 28 days, we can start to bring the slab down to freezing.If we can create a slab of concrete, perfectly flat and even, control the curing, it will not crack, regardless of the size.If you want, I will post a shot of the pour on or about the 31st of October, FYI.Gabe

12. 
    splintergroupie_ | Oct 17, 2000 03:00am | #16

    *Saw you there GC'ing the biggest ice rink ever...(You never saw it coming, did you, Gabe Gabe?)

13. 
    Bob_Walker | Oct 17, 2000 09:12am | #17

    *Gabe,Fascinating. Question: you said "As you know, we install control joints by cutting into the concrete by an inch or so. This will make a weak pattern for the crack to follow, instead of randomly following the thinner patterns in the poured slab." I assume you mean "Generally, with slabs ... but with the special care we use on a rink ...."Just curious; I've often heard it said that "slabs will always crack" but I guess it would be more accurate to say "without expensive steps to ensure accuracy and curing (which generally aren't economically feasible in residential construction, slabs will always crack."Is this right?Bob

14. 
    Gabe_Martel | Oct 17, 2000 01:29pm | #18

    *Bob,Yes, that's correct.Concrete is not a new product but it's one that's been abused on most sites.A sudden change in temperature, thickness variations, inconsistent pouring, inconsistent batching, even the poor installation of rebar can all crack a slab. On a rink slab, it's common to have the concrete on the cold side to pull away from the warm side by a half inch. This shrinkage would crack most slabs.GabeGabe

15. 
    John_Sprung | Oct 20, 2000 08:44pm | #19

    *Preventing permafrost under the slab.... Why would you need to do that? Is it that the permafrost would expand unevenly and crack or tip part of the slab? BTW, how thick is the ice?-- J.S.

16. 
    Phill_Giles | Oct 20, 2000 09:01pm | #20

    *I don't know anything about skating rinks, but I have some exerience with curling rinks. A lot of people think that ice should be as cold as possible; but, in fact, it has to be in a very narrow range of temperature and they can't control that if you have a large mass under the rink that's been super-cooled while they were making the ice (remember, the air inside the rink is generally around 50F when in use, goes down into the high 30's at night and goes up and down like crazy as people come and go, the sun heats the walls, etc.). Next, you have to be able to melt the ice now and then is a fairly short period of time; just turning off the ice-making equipment won't do it, and, as before, if you have a couple of feet of below freezing mass below the rink, it can take days. A curling rink has about 1/2" of ice.

17. 
    Gabe_Martel | Oct 20, 2000 09:05pm | #21

    *Hi John,Yes the permafrost would heave the slab. Rinks that are designed to be used 12 months of the year must have heating lines that are controled by sensors underneath.The ice is about 1" thick.Gabe

18. 
    blue_eyed_devil_ | Oct 21, 2000 02:28am | #22

    *Phill, I love curling (watching it). I know, I'm nuts! Anyways, how much do a set of stones cost?blue

19. 
    Phill_Giles | Oct 21, 2000 04:49am | #23

    *Don't know anymore Blue - they're not even the real article anymore, now they use any old marble and just put an insert of the real highlands stuff in the bottom to ride on. Forty years ago they went in $250 each range.

20. 
    blue_eyed_devil_ | Oct 21, 2000 04:58am | #24

    *$250 each?!!!!I'm thinking like $50 for the whole set!blue

21. 
    Phill_Giles | Oct 21, 2000 05:14am | #25

    *Well, they probably mass produce them now (I quit curling in the 80's when I started to travel so much I was never there for my games - my wife hated the game anyway) and I'm sure that, and the cheaper materials have lowered the cost; but, the old stones were hand turned out of solid highlands marble to a fine polish. Shipping from Scotland alone (the old stones weighed roughly 44 pounds, the newer stones are closer to 40 as the marble is less dense) was probably $50 each.

22. 
    blue_eyed_devil_ | Oct 21, 2000 05:17am | #26

    *I don't want to join a league or anything. i just want to try it out on my lake this winter.Maybe I'll booger them out of a microlam or something.'blue

23. 
    Phill_Giles | Oct 21, 2000 06:29am | #27

    *Most curling clubs have open house/try it days at the beginning of the season; call around to the clubs in your area - nothing to lose, and you'll get enough instruction that you won't hurt yourself too badly.

24. 
    blue_eyed_devil_ | Oct 21, 2000 07:08am | #28

    *I might just do that, thanks for the suggestion.Then again, I might not, now that I think about my back...blue

25. 
    Phill_Giles | Oct 21, 2000 07:23am | #29

    *What was I thinking: "marble", it's been a long day - GRANITE, they're made out of granite.

26. 
    Cliff._Johnston | Oct 22, 2000 03:07am | #30

    *Johnnie,Glad you asked that question - I've wondered about it too. Now if the other respondents would take a remedial course in English comprehension we might get an answer to your excellent question.Cliff.

27. 
    rocko_the_rockn_fool | Oct 26, 2000 03:52am | #31

    *i thought the ? was about lazers v/s transits not rinks,mud or curling

28. 
    blue_eyed_devil_ | Oct 27, 2000 03:04am | #32

    *Rocko, that info got sorted out after about ten posts.Welcome to breaktime.Are you a rocker?blue

2. 
   Johnnie_Browne | Oct 27, 2000 03:04am | #33

   *
   How does the orginal builder level compare to the lazer in accuracy. I know reading the rod at distance is human error but how does this compare to the lazer at distance.